The Compatibility Constant
by RickyTheMonkey
Summary: Amy is facing changes at work and with her family. But the one part of her life that she would like to see progress - her relationship - remains a steady constant... which Amy sees as a source of both comfort and frustration. Will her boyfriend be able to keep up with her changing life? Rated "T" for future developments.
1. Chapter 1: The Parallel Possibility

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 1: The Parallel Possibility**

* * *

"So you see, Amy, there's no way to go beyond a 10th dimension. That's all there can be… at least, so far as we understand it."

Sheldon was trying to explain the intricacies of string theory to Amy. While she grasped the basics of quantum physics, she was by no means an expert. She had dedicated her life to neurobiology.

Sheldon didn't care much for biology - so other than key updates in the advancements of the nicotine addiction study she had previously been involved with, Amy tried to avoid conversations about her own work. However, Sheldon could go on for hours about bosons and quarks… about space-time and the multiverse. She'd gladly let him jabber on, so long as they were spending time together.

"And Parallel universes are a key part of M-theory, which is sort of an encompassment of other versions of string," Sheldon continued.

If she was being completely honest, Amy did find his work fascinating. But she mostly just wanted to spend time with her boyfriend. It made him happy to go on and on. And if he was happy, she was happy. Amy leaned in towards Sheldon to show her interest.

Sheldon was comfortably seated in his spot; his hands waving as he attempted to help her visualize the expanse of the universe.

"In theory, there could be an infinite number of parallel universes. Which means that literally anything you can think of actually is happening in a parallel universe. There could be infinite numbers of you and me out there, Amy. Slightly different, of course, but there nonetheless."

_Interesting_, Amy thought to herself. So that means… in an alternate universe an alternate version of her could be dating an alternate version of Sheldon. The Amy and Sheldon in the parallel universe could be just like any normal love-struck couple in this universe. They would touch… hug… _kiss_.

Interesting, indeed. She was beginning to see string theory's appeal.

It was fun to think about, but she wouldn't trade what she had with _this_ Sheldon in _this_ moment for anything. Their relationship may not be conventional, and - sure - she wished that it was progressing a bit faster, but she knew what they had was real.

"See, Amy, isn't physics so much better than biology?" Sheldon nudged.

Amy smirked. "'Better' is a relative term, Sheldon. While I admit that physics - specifically string theory - is intriguing… biology is just as in-depth and has arguably more real-world application than an unproven theory that involves multiple universes and dimensions."

Sheldon let out an offended gasp, but didn't have time to retaliate. The moment was interrupted as his roommate walked through the door, followed closely by his own girlfriend.

Leonard smiled at Amy as he closed the door. Penny waved at them and made a beeline for the fridge to grab a bottle of water.

"Hi, Amy! I didn't know you would be over here. How has work been going?" Leonard asked.

"To be honest, it could be better," she frowned. She had been kicked off the addiction study after an unfortunate incident with one of the primates. She truly missed the project. Not to mention, she had already devoted so much time and energy to it that it felt like a big piece of her life had been stolen away.

"Oh, that's right," Leonard remembered. "Any new projects on the horizon?"

"Nothing yet," Amy replied.

Penny plopped down next to Amy on the couch and put a consoling arm around her.

"Oh, Ames, something good will come along soon, I'm sure of it!"

Amy couldn't help but smile at her bestie. Her optimism was contagious.

"Thanks you two."

Sheldon sighed and walked over to his computer, obviously annoyed that the focus had been shifted away from his work. The others ignored him, and Amy shifted into Sheldon's vacant spot to give Penny some more room on the couch.

"Well, I have some good news!" Penny exclaimed.

Amy was eager to grab onto anything to help lighten the mood, which had taken an abrupt nose-dive while discussing her work.

"What's that, bestie?"

"I got a part in another play!"

"Really?! That's amazing! What's the part?"

"She's going to be Maggie from Cat on a Hot Tin Roof!" Leonard interrupted. Penny glared at Leonard for stealing her opportunity to deliver the news herself. Leonard immediately wandered to the kitchen to avoid being hit by his girlfriend.

"Wow, Penny!" Amy exclaimed. Penny's good mood quickly returned when she noticed her friend's huge grin.

"Apparently, they saw my performance in A Streetcar Named Desire and thought I would be perfect for the part!"

"Well, that's no surprise. You were amazing in that play."

Amy glanced over at Sheldon - feverishly clicking away at his mouse. It looked like he was playing some kind of simulated city game.

"Sheldon - did you hear what Penny said? Aren't you going to congratulate her?"

"Of course I heard her, Amy. I hear everything." Sheldon paused his game and turned around in his chair. "But is it really Penny that deserves congratulating? She's merely doing her job. The people you should be congratulating are the casting managers who were able to recognize her talent. Penny is obviously a good actress, though her singing ability leaves a lot to be desired."

Penny's eyes began to tear up.

"I'm merely stating a fact, Penny. No need to get emotional." Sheldon rolled his eyes and returned to the game.

Penny and Amy exchanged their own eye rolls, but both knew that even though Sheldon's compliment was buried inside of a somewhat-insult, it meant a lot coming from him.

Standing up, Amy reached down and gave her friend a huge hug.

"You'll do great," Amy said. "Be sure to save me a ticket for opening night."

"Of course! Are you leaving?"

"Yes. I need to get home and do some laundry."

Sheldon paused his game again and turned back around. "You're going home?"

"Yes, Sheldon. I've been here for hours. You of all people know the importance of laundry night."

Sheldon gave an understanding nod, but Amy noted a hint of dejection in his eyes.

"Very well," Sheldon said. "I'll talk to you tomorrow and give you the details of our date night." He turned back to his computer game.

Amy smiled and waved at Leonard and Penny before heading out the door.

As she scaled down the four flights of stairs to the lobby, Amy pondered her boyfriend. Despite his obvious social awkwardness, he had moments of true - albeit typically accidental - sensitivity. Unfortunately, they were often masked by his inability to pick up on social cues, and his habit of coming off to the unknowing onlooker as, well, an ass.

_I can't fault him for his idiosyncrasies_, she thought. _They're what make him special_. After all, not too long ago Amy had a very similar attitude. Over the past couple years, though, she had opened herself up to her friends, and they had helped her slowly break out of her shell. She knew she still had a ways to go, but she was becoming increasingly comfortable in social situations, and had over the past few months really begun feeling an urge to move forward in her relationship with Sheldon.

Of course, Sheldon had to be ready to progress too, and he had yet to put even a tiny hole in _his_ shell… though, he was getting closer every day. He was softly tapping away at it, and Amy knew the shell would eventually crack.

_This is when a parallel universe Sheldon would make it so much easier_, Amy laughed to herself.

* * *

**Chapter two coming soon!**

**Notes:** This is my first fan-fic, so I am very open to reviews and constructive criticism. Thank you in advance!

Also, please note that I am by no means a physicist OR a biologist. I have a very limited understanding of string theory, so if it's not entirely accurate – I apologize. I will do my best with my basic knowledge of the field whenever it appears in this story. :o)


	2. Chapter 2: The Stargazing Reaction

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 2: The Stargazing Reaction**

* * *

It was Thursday prevening – a word Sheldon had invented to describe the "ambiguous time between afternoon and evening" – and Amy was spending a few minutes to decompress after a busy day at work before she needed to begin getting ready for their date.

She was relaxing in her tub, thinking about the day's events.

Her boss had finally given her the opportunity to participate in a new study. He'd been sure to point out that Amy "couldn't start any trouble", since it didn't involve any animal interaction.

The project was a year-long analysis of the brain's reaction to various visual and audio stimuli, comparing the effects based on gender, race and age. She and a coworker would be using music, video, and other imagery to achieve their results.

Amy had jumped at the opportunity to be involved in a new project. She had been so bored just cleaning up her lab and filling out paperwork that she probably would have accepted no matter what had been offered to her. It was a bonus that she was genuinely intrigued by what the results of the study would be.

Amy got out of the bath and dried off. It was still about an hour before Sheldon was scheduled to arrive, but she wanted to spend a little extra time getting ready tonight.

Even though she and Sheldon were together on a regular basis, "date nights" just felt different. She always took a bit more care with her appearance when she knew it was a night set-aside specifically for them. Even though the outcome of the extra time spent on herself was never drastically different from her everyday appearance, she liked knowing that her hair was properly pinned back and her clothes were freshly ironed.

Once she was satisfied with how she looked, Amy went to the living room to check her email and spend the last few minutes before their date watching the news.

She no more than sat down when she felt her phone vibrate in her pocket. Pulling it out, she noticed it was her mother calling.

Ordinarily, she would have answered. She enjoyed talking to her mom, so long as it wasn't about her relationship with Sheldon. Inevitably, though, there would be some point in the conversation when the topic would come up - and Amy didn't feel like discussing Sheldon with her mother right before going on a date. She wanted to be in the best mood possible for the evening.

Amy silenced her phone and tucked it away in her purse.

Just then, Sheldon's signature knock echoed through the living room. She smiled and scurried to the door to greet her boyfriend.

"Hello, Sheldon!"

"Hi, Amy - are you ready for our date?"

"I certainly am! Would you like to come in for a beverage, or do you want to leave straight-away?"

"Thanks for the offer, Amy, but I think we need to leave now if we are going to eat and make it to the planetarium in time for the show."

Amy nodded and stepped into the hallway, pulling the door closed behind her. Sheldon waited patiently as she locked the door and put her key away.

As they walked side-by-side down the hallway, Amy noticed Sheldon seemed distant. More-so than usual.

"Is something wrong, Sheldon?" Amy asked as he held the door open for her to step outside. The air had a chill in it. She was glad she had decided to wear a sweater.

Sheldon didn't say anything for a moment then turned to Amy.

"Amy, am I a bad boyfriend?"

Amy literally stopped in her tracks. That's not what she had been expecting at all.

"Why would you think that?"

"Something Leonard said yesterday after you left."

"What did he say?" Amy began walking again, looking down at the sidewalk. She couldn't imagine what would have given him the impression that he was a bad boyfriend. She certainly didn't think he was, and began racking her brain to figure out what she may have said or done for Leonard to think she wasn't happy.

"He just said that most women would like their boyfriends to give them a kiss goodbye. I don't do that." He paused a moment before adding "Does that make me a bad boyfriend?"

"Certainly not, Sheldon!"

They had reached the car, but stood outside it without opening the doors. Sheldon didn't appear to be convinced by her response.

"Sheldon," Amy continued. "You and I both agreed to keep the physical side of our relationship the same as it was before we began dating. If I wasn't okay with that, then I wouldn't have agreed to it. And if it seems as though I am pushing you into a physical relationship, I do apologize. That is not my intention."

Sheldon was looking at Amy's hands, as if it was too hard to meet her gaze.

"I don't feel like your pushing me at all," Sheldon insisted. "It's the other people that are the problem."

"I agree." Amy said it with such finality that Sheldon finally looked up. She didn't want their date to start off on a bad footing. She popped open her door and motioned for Sheldon to do the same.

"Gotta get going, Sheldon."

"Of course. We don't want to be late."

Sheldon's mood was beginning to improve. He opened his door and slid into the passenger's seat. As he buckled his seatbelt, he looked over at Amy, who was starting the car and shifting into reverse.

"So - just to be sure - you're okay where we are in our relationship right now?"

Amy sighed. "Yes, Sheldon, I am."

It wasn't entirely accurate. She was happy with him - that much was true. But she did secretly want to see more improvement in the romantic side of their relationship. Of course, if she admitted that, she'd scare him away.

"Are _you_ okay with our relationship?" Amy added.

"Oh yes. I wouldn't change anything about it!"

_Of course you wouldn't. _She gave him a small grin and pulled out of the parking lot.

* * *

Sheldon had arranged for them to eat dinner at his favorite Chinese restaurant. It had the fastest service, which would allow them to get in and out quickly in order to make it to the planetarium in time.

As they were eating, Amy decided to broach the topic of her work. She did, after all, have some major developments to report.

"Sheldon, I'm going to be on a project again at the university."

He looked up from his dumpling. "Oh? Are they allowing you back into the addiction study?"

Amy was pleased that he seemed interested. "No, actually, its an entirely new project."

The waitress came by to refill their drinks. After she left, Amy continued. "I'm actually going to be working with people this time, instead of animals."

"Well that sounds awful."

Amy knew better than to take it personally.

"Yes, well, despite the human interaction, I think it's a great opportunity. It focuses on the affect of outside stimuli on the brain. We'll be comparing the outcomes based on age… gender… race. We're even going to monitor how those patterns change of a period of time. You know… whether the brain can become so accustomed to certain stimuli that the neurons begin reacting differently."

Sheldon swallowed a mouthful of tangerine chicken. "Well, it's not the unification of gravity with quantum mechanics… but I'm still happy for you."

Amy's phone buzzed in her purse. She groped around in her bag and pulled it out.

It was her mom again. _I wonder what she wants_…

"Who is calling you? All our friends know it's our date night."

"It's my mom. I'm letting it go to voicemail." The missed call alert chimed and Amy placed the phone back into her bag.

"You should have answered the phone, Amy. What if it's important?"

Amy knew Sheldon despised it when people didn't answer phone calls. Part of his obsessive need for closure, she deduced. However, she also knew he didn't like his schedule to be interrupted.

"I'm sure it's not important. I'll call her back later. Besides, we have to get going if we expect to make it to the planetarium in time. The presentation starts at 7:30."

Sheldon pulled out his pocket watch and looked at the time.

"You're right. We should go."

As Sheldon paid the check, Amy checked her phone for a voicemail. Her mother hadn't left one.

_Strange_, Amy thought.

* * *

The planetarium was amazing, as usual.

Sheldon and Amy had been to the there on previous date nights. Aside from the zoo and museum, the planetarium was one of their favorite activities. And tonight, there was a special presentation on black holes. It was right up Sheldon's alley.

The place was surprisingly busy for a weeknight. She assumed that most of the people in attendance were high school or college students coming for extra credit. Most were either quietly whispering or sleeping.

She scanned the dim room. There were a few other couples in the crowd - you could pick them out easily. They were the ones snuggled up together gazing at each other rather than the stars.

Amy was sure that anyone looking at herself and Sheldon would consider them nothing more than a pair of grad students. If they hadn't seen the two of them come in together, they probably would even assume that they were strangers.

Amy glanced over to Sheldon. The artificially lit stars reflected in his big awe-struck eyes. He was in metaphorical heaven.

Without thinking she impulsively reached through the darkness to grab his hand. The second she did it she regretted it.

They had _just_ finished discussing the fact that they were at a good place in their relationship and here she was grabbing him in the dark. The deed was done, though. She couldn't just pretend it was an accident. Her hand loosely held his as she quickly looked back at the ceiling illuminated with thousands of stars.

She could feel Sheldon look down at her hand clasped over his. He made no attempt to hold her hand back. Instead he just shifted uncomfortably in his seat.

Amy waited a few more minutes then slowly pulled her hand back. Leaving Sheldon free to immediately drop his own hands into his lap.

_What came over me?_ She hadn't intended to grab his hand. It just happened.

She could feel the tension between Sheldon and herself. Out of the corner of her eye she could see that his eyes were still locked on the black hole presentation, but she knew that was no longer where his mind was focused. She could almost hear the mental gears in his head turning… trying to figure her out.

_Great_, Amy thought. _Now he's never going to believe that I'm okay with our relationship where it is. He's going to think I was lying before._

The awkwardness continued until the presentation ended and everyone began to file out of the auditorium.

They managed to make it to the car without speaking and began the short drive back to Sheldon's apartment. After a while, her boyfriend broke the silence.

"It wasn't true, was it? What you said about our relationship earlier, I mean."

Amy heaved a big sigh. _I knew it... _

* * *

**Chapter three coming soon!**

**Notes:** This is my first fan-fic, so I am very open to reviews and constructive criticism. Thank you in advance!

And thank you to those who have already commented on my first chapter! It is greatly appreciated!


	3. Chapter 3: The Impulse Hypothesis

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 3: The Impulse Hypothesis**

* * *

"I wasn't lying, Sheldon."

She pulled her car up outside his apartment and put it in park.

Amy turned to her boyfriend. There was no way to explain her behavior without explaining her … desires… to him. She decided to just bite the bullet.

"Look," she began. "I wasn't lying before when I told you I was happy with our relationship. Of course I am! But I should add that I do occasionally feel the urge to … _touch_… you."

Sheldon looked up at her with shock. "Amy… you know I don't like touching."

"Of course I know that… you're my boyfriend. I know _you._ It's just that … while I am happy just being next to you, sometimes I want to _feel_ you. It comforts me. It doesn't mean I'm trying to push you into a physical relationship."

Then, suddenly, she remembered something. "Sheldon… you feel the same way I do."

"What?"

"You remember Howard's launch. You grabbed my hand."

The realization spread across his eyes. She was right, of course. Amy knew in that moment that she would ultimately win this argument.

"Yes, I remember," Sheldon conceded. "I don't know why I did that."

"I do," Amy said.

Sheldon shot her a derisive look. "Amy, how could you possibly know what I am thinking?"

"Because it's the same thing I was thinking in the planetarium."

"What _were_ you thinking?"

"That's just it - I wasn't. I just felt the urge to grab your hand so I did. That's exactly what you did at the launch. You were acting compulsively."

Sheldon considered her. "I'm a physicist, Amy. I never do anything without thinking about it first. But let's assume I agree with you… If I wasn't thinking, what could have possibly caused me to reach for you?"

"It's like I said, Sheldon. You wanted comfort… just like I did in the planetarium. Flu shots are not the only time people need a little extra support, you know." She paused, then a sly grin spread across her face. "Sheldon, you're a genius, right?"

He just gave her an exasperated look.

"_Right_…" she shuffled in her seat. "I _meant_ to say: Sheldon, you _are_ a genius. By your own admission, your brain is constantly processing information. Rarely do you make mistakes… would you agree?"

Sheldon nodded.

"So, if your brain is in a constant state of thought and you were acting on your _own_ impulse when you grabbed my hand at the launch… that _must_ mean that your _highly intelligent _subconscious was acting of its own accord. There's no way there could be anything wrong with you grabbing my hand." She paused to let that sink in.

"In fact," Amy added, "One could argue, that if your subconscious urged you to do it, then it was only logical to follow through."

She was pleased with her quick wit. She could tell Sheldon was really mulling her words over.

"That's an intriguing hypothesis," he said. Then a smile came over his face. "I must say, Amy, that makes me feel a lot better. There's nobody I trust more than myself."

Amy nodded.

"And If I trusted myself to grab your hand," Sheldon continued, "Then you should certainly be afforded the same opportunity."

Amy nodded, "Thank you, Sheldon." She could tell he was satisfied with her conclusion.

They sat in a comfortable silence for a moment.

"So... does this mean we can start hold hands, now?" Amy urged.

Based on Sheldon's look, you would have thought she had suggested they run naked down the street.

"Amy - we aren't hippies!"

"But, you just said -"

"No, I said it was ok if it was done on impulse. That makes sense to me. There's no reason to start holding hands _all_ the time. The next thing you'll want to do is cuddle every time we are on the couch."

Amy remembered the time Sheldon had allowed her to cuddle with him. It had taken some convincing, but, ultimately he agreed to provide her with the added comfort she needed during a time of distress.

Finally, Sheldon unbuckled his seatbelt and began to gather his messenger bag, signaling that he was done with the conversation. Amy didn't press the issue. She'd already achieved more than she expected she would that evening. No need to force anything else.

"Have a good night, Sheldon."

"You too, Amy."

He pulled himself out of the car and shuffled to the apartment complex, shooting one quick glance back in Amy's direction as he walked inside.

Amy relaxed in her seat for a moment before pulling her phone out of her purse to text Penny about her wonderful date night.

Two more missed call alerts popped across her home screen - both from her mom. But she hadn't left any voicemails.

_How bizarre_. If it was important enough, certainly she would have left a message.

Amy glanced at the time. It was after 10:00, which meant it was almost 1:00 a.m. at her parent's home in Philadelphia. It was too late to call back now. She'd have to return her mom's calls in the morning.

It wasn't too late to text her bestie, though. Amy grinned as her fingers brushed across the keypad.

_-Had a great date with Sheldon! I'll fill you in on the details on our next girls' night!-_

Penny texted back almost immediately.

_-Thats fantastic! We'll have to get together soon!-_

Amy set her phone in her empty cupholder and pulled away from the curb.

She suddenly felt drained. She had to get home and get to bed. Her new work project was starting in the morning and she needed to wake up refreshed.

* * *

Amy slapped her hand onto the alarm clock blaring on her bedside table. She groggily rubbed the sleep out of her eyes and squinted at it.

_Did 6:00 a.m. always come this early?_

Despite being exhausted, it had taken longer than she had hoped to fall asleep. She just couldn't turn her mind off after the evening with Sheldon. She'd pay for it this morning, though.

Amy forced herself out of bed and dragged her feet all the way to the bathroom to get ready for the day. By the time she left her apartment, she was finally wide awake and eager to get started on her new study at work.

When she got to her lab, she eagerly grabbed her charts and notebook and met with her new lab partner, Hannah.

Amy knew Hannah pretty well, though they had never directly worked with each other. She was cute… nice… tall. Her naturally red hair was dyed a very unnatural and even brighter shade of red... and Hannah always wore different colored glasses. Amy estimated that she must own at least twenty-three pairs in just about any color imaginable. Today's were bright purple.

When the door clicked shut behind Amy, Hannah looked up from the clipboard she was studying and smiled.

"Amy! It's great to finally be working with you! Just us girls!"

Amy sat down at the lab desk beside her co-worker. Hannah slid her a packet filled with the initial paperwork laying out the parameters of the study. She was already halfway through her packet, so stopped to let Amy catch up.

"It looks like the first week or so of the project is going to be pretty dull," Hannah said. "Its all paperwork and choosing the subjects to participate in the study."

Amy nodded. Hannah was right. The beginning of a project was always the most boring part of the process - but was necessary to ensure that the results at the end of the year were as accurate as possible. Even though it wasn't very exciting, it was still extremely tiring work.

As the day wore on, Hannah and Amy grew very comfortable with each other. It was as if they had worked together for years. Finally, Hannah set down her pen and stretched her arms out in front of her. They had been sitting in the uncomfortable lab chairs for the better part of four hours.

"Amy, I always knew I would probably like you," Hannah said. "I'm glad I was right. It would really suck to have to spend a year with some of the other pretentious people who work here." She gestured towards the door.

Amy glanced over her shoulder. A few other people from her department were grouped together in the hallway laughing about something. She shrugged and looked back at her paperwork. Amy didn't have an opinion of any of the other people who worked there, as she often worked alone. She hadn't had much time to get to know anyone too well. Hannah was probably the one she was most familiar with, but only because they were very similar when it came to work. They both kept to themselves, for the most part.

"Well, I'm glad to be working with you too, Hannah. I can't wait until we really dive in to the nitty-gritty part of the study."

Amy noticed Hannah fiddling with a ring on her hand.

"Are you married?" Amy asked.

Hannah spread her fingers out in front of her and looked at the ring on her left hand. "Engaged," she said. "His name is Mark. We're supposed to be getting married in April."

"Supposed to be?" Amy sensed there was trouble in paradise, but didn't want to appear nosy.

Hannah didn't seem offended by the question. She was surprisingly at ease given the topic.

"Yes. Well. We are trying to work things out. We've been engaged for two months. We met last year."

_One year?! One year and they're already getting married?_ She couldn't fathom a relationship moving that fast. Even if she wasn't dating someone who insisted on moving at a snail's pace.

Amy didn't want to press Hannah for any more details about what appeared to be a temultuous relationship. After all, she wasn't one to criticize. Her own relationship wasn't perfect.

"How about you?" Hannah questioned.

"Me?"

"Yeah. Is there a fella in your life?" Hannah smirked and nudged Amy's arm.

Amy blushed. "Yes. Sheldon. We've been together for a few years."

"Oh wow… sounds serious. Are you two considering marriage yet?"

Amy couldn't hold back a small snicker. She couldn't even begin to describe her relationship to Sheldon with someone outside of her close circle of friends - let alone someone like Hannah who had only met her fiancé a few months before getting engaged. She would never understand.

"No. Not yet." Amy left it at that.

Hannah seemed satisfied. She picked up her clipboard and continued down the list of items inventoried for their project.

Amy quickly busied herself with her own work, too.

* * *

**Chapter four coming soon!**

**Note:** Once again, thank you for any reviews and constructive criticism you may provide! Also - I feel the need to again note that I have no real in-depth understanding of biology or how studies like this are conducted. I'm kind of just batting in the dark and trying to make it as realistic as possible. I apologize if it is inaccurate in that regard.

Also - My next update may not be for a few days. It is difficult for me to focus on anything but work during the week, so the easiest time for me to make any updates is on weekends! I'll do my best, though!


	4. Chapter 4: The Incoming Variable

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 4: The Incoming Variable**

* * *

Amy threw her purse and jacket into the chair next to her door. She was finally back at her apartment after a long, busy day at work.

She'd been so engrossed in the initial day of the new study that she hadn't even taken a lunch break. After kicking off her shoes, she shuffled to the kitchen and poured herself a bowl of cereal then sank into the couch to unwind.

Despite being exhausted, she was happy that the past couple of days had been so exhilarating. She had made small, but meaningful progress in her relationship with Sheldon, and began a very important step in her career. All in all, she was on cloud nine. _Even Shredded Wheat tastes better tonight_, she thought. But that might have just been because she was extra hungry.

A lot of updates for girls' night, that much was certain.

That reminded her… she needed to text Penny.

She pulled out her phone and noticed that her friend had already beaten her to the punch. Penny's text was there waiting for her.

- _Hey Ames! Girls night 2morrow ok?_ -

Amy texted back a confirmation to Penny to let her know that she was looking forward to it, then decided to get cleaned up and ready for bed.

Just as she had gathered her towel and heated up the shower, she heard her phone buzzing. It took her a few seconds to dig through the pile of folded laundry that she had tossed it into, and by the time she found the vibrating device the call had ended.

She glanced at the screen.

-_Missed Call: Mom_-

_She must really need to talk to me_. Amy decided to call her mom back after she had taken her shower and settled in for the evening.

She turned the volume up on her phone and set it next to her computer, then went to the bathroom to wash up. She spent the majority of her shower time just letting the warm water rush over her while she sang a rousing chorus of "Walking on Sunshine". In the last few minutes, decided she had better actually clean herself and began washing her hair.

When she emerged from the bathroom, she noticed she had missed yet another call from her mom. _Must be pretty important. _Amy picked up her cell and swiped her finger across the screen. After only two rings her mother answered.

"Amy!" Her mother was ordinarily a very soft-spoken woman, but right now it sounded like she'd been running a marathon.

"What's going on mom?"

"I've been trying to reach you for days. Where have you been?"

"Yes. I'm sorry. I just have been so busy at work... and was in the shower when you called earlier." _Not a total lie._

"Well, I didn't want to leave a voicemail. I wanted to actually talk to you so that I could tell you the good news!"

Amy sat down on the couch and rubbed her damp hair with her towel.

"Good news?" Amy parroted.

"Yes! Two bits of good news, actually. You're father will be going to work near Pasadena!"

"Really?! That's amazing!" Amy's father often traveled for work, and Amy loved seeing him whenever he came into town... which was rare. If he would be around Pasadena for a few weeks, then she would have to come up with some fun things for them to do together.

"How long will you have to manage without him?" Amy asked. "Will dad be splitting his time between California and Pennsylvania? Does he need a place to stay for a few days?"

"Oh, no. That's the second part of our good news! The job isn't temporary... he was offered a permanent position. We are both going to be moving out there!"

Amy was speechless. _My parents are moving here?_ Her brain suddenly was unable to function properly. She couldn't process the information she'd just been given. _Is this good news or bad news?_ She wasn't sure.

Of course, she always wanted to spend more time with her parents, but she also felt very independent living on her own so far away from them. Then there was Sheldon to consider. How would _they_ get along?

"Amy?"

Amy realized that she hadn't said anything for a while. She didn't know exactly how long it had been.

"That's... wonderful!" She said with forced enthusiasm. "When will you be moving?"

"We are packing now, actually. Dad has to be there on Tuesday for work. We've been running around like crazy people! We decided to store what we can now, and fly out there on Monday to start looking for a house. In about a week - after your dad gets settled in at his office - I'll return here and finish up with the packing. We're going to hire movers to drive all of our belongings to Pasadena."

_Monday?!_ That was in three days! This was happening so fast. Amy had a great relationship with her parents, but she couldn't explain this gut feeling that them living near her may cause some problems.

_Stop being foolish,_ Amy thought to herself._ They are your parents. You love them. It will be great to see them more often._

"That's amazing, mom. Really."

"Isn't it? Dad hasn't had a chance to talk to that boyfriend of yours yet. Sheldon, is it?"

Amy nodded, but said nothing. Her mom continued on, oblivious to her daughter's inaudible response. "He'd love to meet him. And I'd like to see him _in person_ as well."

The added emphasis on the phrase 'in person' did not go unnoticed by Amy. She knew that her mom didn't believe that she was actually dating Sheldon.

Following their first meeting during a Skype-session ruse in the early stages of she and Sheldon's friendship, Amy had eventually felt compelled to tell her mother the truth… that they weren't actually dating. The problem was that once Sheldon and Amy _did_ officially upgrade their relationship status, her mom didn't believe her. After the incident with Sheldon and a previous fable about a miniature horse-breeder named Arman, Amy had become the girl who cried 'wolf'.

Despite the fact that her mom didn't believe Amy's story, she had been 'playing along' with it. Amy, of course, had always been able to tell her mom was skeptical of the relationship.

Amy responded with confidence, in an effort to prove to her mother that she wasn't lying. "Sheldon would love to meet you too, I'm sure."

She wasn't sure. In fact, she knew for certain that Sheldon did not have any interest in meeting her family. Amy had aunts and cousins in the area, and had been trying to get him to go to family gatherings for years to no avail. It was like pulling teeth from a crocodile. Another fact that just added fuel to her mother's doubts about their relationship.

"Well, great!" Amy's mom continued. An air of disbelief still hung in her voice. "I'll give you a call when we get into town and we can meet up. You can show us all your hang-outs!"

"Okay."

"Goodnight, Amy. See you soon."

"'Night, mom."

Amy hung up the phone and sat in silence for a good ten minutes.

_I should be happy about this,_ Amy tried to convince herself. She did miss them - but she had this unexplainable ... _feeling_... in the pit of her stomach.

And how would Sheldon react? This would mean he would no longer be able to hide from Amy's family. Her parents would most likely be within a twenty mile radius of them, and would certainly want to spontaneously get together from time to time. They wouldn't understand Sheldon and his need for routine. For structure.

_This will undoubtably force him into some awkward situations_, Amy thought. _He'll start to put up a wall._

Amy was determined not to let that happen.

She was going to make sure to review the section of their Relationship Agreement pertaining to family visits and gatherings before talking to him.

* * *

**Chapter five coming soon!**

**Notes:** I found time to update after all! :o) As always, reviews and constructive criticism are encouraged and appreciated!

Also - As of the writing of this fanfic (the past part of Season 6), not much has been revealed about Amy's family on screen. So, if that information is released in later seasons, this story may become obsolete. Until then, though... we can use our imagination!


	5. Chapter 5: The Schrodinger Conundrum

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 5: The Schrodinger Conundrum**

* * *

"Amy? Are you listening to me?"

Penny's voice pulled Amy back to the present. She had been lost in her own mind… trying to figure out a way to mention to Sheldon that her parents would be moving to the area.

"Hm?" Amy asked.

"Where are you today? Whatcha thinking about?"

"Oh nothing. Just work stuff,' she lied.

"It's the weekend, girl! That can wait until Monday! We have a girls' night to plan!"

Amy and Penny were in Leonard and Sheldon's apartment. While the boys played video games, the girls had decided spend some time chatting in the kitchen.

"Why don't we go to a movie?" Amy blew on her cup of tea to cool it down.

Penny squished her face in disgust. "No, Ames. We can't talk in a theater. We need to spend time catching up on each other's gossip." She lowered her voice and added, "Remember… you have to fill me in on you-know-who." She nudged her head in Sheldon's direction.

Amy looked over at her boyfriend. His face was fixed on the TV screen with so much intensity you would have thought he was performing surgery. His fingers swiftly moved from button to button on his game controller.

_My parents definitely aren't going to understand our relationship_. Now that she was thinking about it, girls' night would be the perfect time to try and figure out how to bring up this topic with Sheldon. Her best friends would know what to do.

Amy smiled at Penny. "You're right. We definitely need to chat. How about we go to the club down on Del Mar… where we went last time?"

"Much better! I'll let Bernadette know."

Penny quickly sent a text to the third member of their chick trio.

* * *

Later that night, Amy, Penny and Bernadette had abandoned their men in apartment 4A, and were sitting at a tall, round table sipping on their respective adult beverages.

Amy hadn't even made it halfway through her glass of wine yet, but Penny had already downed a couple drinks and was starting to get tipsy.

Bernadette had left the other two in the dust. She hadn't been out in awhile and had decided to 'live it up'.

"It's great you have a new project to occupy your time at work, Amy," Bernadette slurred. Despite her obvious impairment, she was managing to stay present in the conversation fairly well. "And it sounds like Hannah will be a great lab partner for you!"

"Boooo! I don't want to hear about work!" Penny whined. "I want to hear the juicy stuff! Ok, Ames, SPILL. What happened between you and Sheldon the other night?"

Bernadette leaned in close and chimed in, "OOOoooooooo…. Something happened?"

Amy shook her head and waved them off. "No. Nothing like that." She was starting to think asking her friends for advice in a bar was a bad idea.

"Wait a minute… you told me you had news! Don't hold back on me, Ames!"

Amy sighed. "It was no big deal. We just held hands. Sort of."

"Ooooooooo…" Bernadette repeated. "Hot stuff!" Amy was annoyed by the sarcasm in Bernadette's voice.

"Actually," Amy continued, "Sheldon wasn't too keen about it at first and got rather upset... but he came around."

"Why was he upset?" Penny's shock seemed genuine, though Amy wasn't sure why. Her bestie had known Sheldon longer than she had.

"You know he isn't a fan of touching. He was just reacting to that. But its fine. We discussed it and everything is great now." After a brief pause, Amy added "… well… except…" Her voice trailed off.

"Except….? " Penny and Bernadette echoed back in unison.

Amy rubbed her hands over her face. "Except that I don't know how to tell Sheldon about something that he may very likely see as bad news."

"You didn't cheat on him, did you?" Penny asked with a surprised look on her face.

Amy gaped at her friend and furrowed her brow. _She's lucky she's cute, _Amy thought.

"Right. Forget I asked," Penny said, throwing up her hands in surrender. She leaned in close once more and whispered, "So… what's up? What's the deal?"

"Well, my parents are coming into town."

"That's wonderful! I'm dying to meet them!" The volume of Bernadette's voice told Amy that her petite friend had probably had enough alcohol.

"Well… you'll have plenty of chances. They're moving here."

Bernadette nearly slipped off her stool. Penny and Amy rushed to catch her and steady her at the table. "Oopsy," Bernadette laughed.

"Maybe we should get you home," Amy said.

"Yeah, maybe," Bernadette relented. Penny grabbed Bernadette's clutch and went up to the bar to close her tab. When she returned, she and Amy helped Bernadette through the crowded floor and into a cab outside. They squeezed in next to her in the back seat.

On the ride home, Amy was pressing Penny for suggestions about how to handle her situation with Sheldon.

"I just don't even know how to begin to bring this topic up, Penny." Amy leaned her head against the window of the cab. It was filthy, but at this moment she didn't really care.

"Amy, have you ever heard of Schrodinger's cat?" Her blonde friend leaned in toward her with a knowing, cheesy grin.

Amy was impressed. Not only because Penny knew about Schrodinger's cat - _where the heck did she pick that up?_ - but mostly because it was actually relevant to the present conversation. Penny was right. She could sit and think about it all night, but eventually Amy would just have to tell Sheldon... and let the chips fall where they may.

"Wow." Amy said. "That's actually helpful."

"Hey! Don't look so surprised! I remember things!"

The cab pulled up outside 2311 Los Robles Ave, and the trio piled out onto the sidewalk.

Amy paid the driver and she and Penny allowed Bernadette to steady herself against them as they walked up the stairs.

Penny didn't even bother knocking on 4-A. She just barged in. The boys were where they had left them earlier… Sheldon, Howie, and Raj on the couch and Leonard in the armchair. They didn't look up from the TV screen until a loud blast and a mutual groan from everyone except Leonard indicated that he had just blown them all away.

Leonard had a smug smirk on his face as he paused the game and looked up at the girls. "Hey! How was girl's night?"

"It was great!" Penny said cheerfully, then turned to Howard. "Howard… your wife needs you."

"Heeey love muffinnnn…" Bernadette waved at the tiny engineer. He looked around at his friends with embarrassment.

"You're lucky she had us with her," Amy added. "There was a rather large woman with quite a bit of chin hair giving her the eye at the club."

"Ok, Bernie. Let's get you home." Howard took his wife's arm and Raj grabbed Bernadette's clutch from Amy as the three of them walked out the door.

Once they left, Penny rested on the arm of Leonard's chair and Amy went to take her place next to her boyfriend on the couch. Sheldon threw a disapproving look in Amy's direction as she sat down. He didn't like it when she drank alcohol. It tended to make her a bit more… handsy. But Amy hadn't had enough to drink tonight to make her crazy enough to try anything like that with Sheldon so soon after what happened on Thursday.

"So are you all going to come to the opening night of my play like you promised?"

Penny's production of Cat on a Hot Tin Roof had already been scheduled for an opening in October, about two months away. Penny was over the moon with excitement. "I can get you all front row tickets!"

Leonard put an arm around his girlfriend and pulled her close. "Well, you know I'll be there." Penny smiled and looked over at Sheldon and Amy.

"Amy? Whatdya say?"

Amy nodded and looked at Sheldon. "You're coming too, right? You enjoyed her last production."

Sheldon looked from Amy to Penny. "Okay."

"Yay! I'll get six tickets! Bernadette and Howard already agreed to go. I'm sure Raj will, too."

"Might want to make it eight," Amy squeaked out. Sheldon turned to her with a confused expression.

"Eight?" He said. "Who else do you know? All the important people are already going... And even some of the unimportant people."

Leonard and Penny exchanged looks. "_Excuse me_...?" Leonard began.

"Oh, not now Leonard." Sheldon didn't even bother to look at him. He was still facing Amy.

"But - " Leonard tried again.

This time it was Amy who interrupted. "Oh, let it go, Leonard, you know it's true."

Leonard pouted and sat back in his chair.

Amy shifted her focus back to Sheldon.

"My parents will be in town that weekend," She said. She wanted to test the waters before confessing that their presence would be more permanent than just a visit.

Sheldon paled a bit, but said nothing. She knew he was trying to think of a way to back out, but he'd already committed to going.

Penny broke the silence. "That's great, Ames!" She winked at Amy. "Two more tickets won't be a problem at all."

Sensing that Amy would need to talk to Sheldon, Penny took Leonard's hand and pulled him up from the chair. "Come on, sweetie… come help me run through my lines." She pulled Leonard through the door and into the hallway before he had time to protest.

With Amy and Sheldon suddenly alone, the silence was palpable. Sheldon spoke first.

"So… your parents, huh?"

Amy nodded. "Yes. I just found out."

She took a breath before continuing. "They are actually going to be here this Monday, too. That's why my mother had been trying to reach me so persistently on our date night."

Sheldon gave her an '_I told you so_' look. Amy ignored him. "What do you think, Sheldon? Since my parents will be here next week, I'm sure they will want to see you. Shall I go ahead and put in the three day's advance notice for a family-related outing, per the relationship agreement's requirements?"

He looked like he was working through a really difficult equation in his head. Finally, he gave up.

"I'll need it in writing, but … I suppose so." She could tell that he didn't want to go, but she was following protocol. He had no choice.

"Very well. We'll go out with them on Tuesday. I'll arrange everything with my parents."

Sheldon nodded. "How long will they be in town?"

Amy had been expecting the question, but wasn't yet prepared for it.

"Er… well… it could be quite a while." She danced around the answer. Sheldon pushed up a questioning eyebrow.

Amy decided just to dive in. _Schrodinger's cat_, she remembered.

"Actually, Sheldon. They are moving here."

Sheldon's eyes widened to the size of golf balls. "To Pasadena?! Oh, Amy… I don't know about this… "

"I don't know, either," Amy quickly said. "But, what can I do? I don't have any control over their decisions." She shrugged. "Besides, I enjoy their company."

"Well, I like it when my mom visits too, but I don't think I could handle it if my mother _moved_ here," Sheldon said. Then he gave a snort. "What am I talking about…. she'd never live here. She thinks California is '_the land of sinners and heathens_'!" Sheldon's mocking of his mother's voice made Amy giggle, and her laughter relaxed him a bit.

"Well, my parents aren't quite the same way," Amy said. "Don't get me wrong… they have their own quirks, for sure. But, I _am_ happy that I will be getting to spend some more time with them. They're great. You'll see."

Sheldon still wasn't convinced. "Well, this means that I will have to rewrite the relationship agreement." He got up and walked over to the kitchen. "Tea?" He asked.

"What do you mean, Sheldon? What's wrong with our agreement?"

Sheldon frowned when she didn't answer his question, but he pulled out a tea bag for her anyway and continued heating the water.

'I mean, _Amy_, that if your family is going to be living here, they will obviously want to spend time with you. We will need to work it out so that you have adequate time both with your parents _and_ with me."

"Oh!"

Sheldon looked up from the kettle on the stove and turned to Amy.

"I'm no expert, Amy, but you sound surprised."

"I am," she admitted. She had been expecting him to want to restrict the amount of time that he was forced to spend with her parents, but instead he was just wanting to preserve his time with her.

"We'll also need make sure that my schedule remains intact. I don't want too many disruptions," Sheldon added, turning back to the tea.

_Ah, there it is_.

* * *

**Chapter six coming soon!**

**Notes:** Please review! I'll buy you a tepid water if you do! ;o)


	6. Chapter 6: The Characteristic Similarity

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 6: The Characteristic Similarity **

* * *

Monday arrived far too quickly for Amy's liking.

Her parents were scheduled to land at LAX around 10:30 a.m. They had bought tickets on the earliest flight possible in order to make it to Pasadena with enough time to get settled into a hotel and begin the house-hunting process.

Amy was planning to take a long lunch and meet up with them.

Fortunately, she didn't have too much time to dwell on her parent's impending arrival, because she had a lot to focus on in the lab.

Hannah and Amy were sifting through the piles of potential candidates for their neuron stimulus study. There were thousands of possibilities contained in several binders in front of them. The pair had to narrow them down to one hundred people who would participate, making sure to maintain enough variety in the individuals' characteristics to fulfill the requirements of the study.

They had divvied the binders between the two of them, and were going over the candidates. Hannah and Amy had decided to choose fifty people each.

"Look at this one," Hannah said, handing Amy a page from her binder. "#4911… she has narcolepsy and she's prone to seizures." As Hannah listed off the given traits provided on that applicant's information sheet, her nose scrunched. "I mean, I sympathize with her plight, but how are we supposed to perform our tests on someone with these limitations? I swear, Amy, narrowing down these candidates is going to be the death of me."

Amy laughed. "Could be worse. Earlier I came across an elderly man with a sex addiction."

"You got me beat." Hannah laughed.

"Well, they do want a wide variety of subjects," Amy said.

"Yeah, but this is a bit too much variety," Hannah set her pen down on #4911's paper.

Amy couldn't help up agree. Many of the potential subjects she had looked at weren't exactly what the study called for. After three hours of work, she had somehow managed to come up with twenty or so candidates who fit the bill, but would definitely have trouble completing her list.

Amy looked at the next page in her binder.

_Subject #5891_  
_Sex: Male  
Age: 30  
Race: Caucasian  
Height: 6'1"  
Weight: 160  
IQ: 174  
Marital Status: Single  
Employment: Chemist/Professor  
Notable Physical or Medical Characteristics: OCD, Haphephobia, Mysophobia, Hypochondria  
Reason for interest in study: To contribute to advancements in the field of neurobiology_

Amy read over it again.

Aside from very minor differences, this subject was extremely similar to Sheldon. Very high intelligence, OCD, works in science… _germaphobe_? Even the reason given for participation in the project was something Sheldon might say. This candidate was the epitome of her boyfriend.

She was immediately curious as to how someone like him would react to the various stimuli that they would be introducing in the study. Since the tests were designed to give them a look at how the subjects' brains reacted to different imagery and sound, this individual could provide Amy with some insight into the mind of her boyfriend.

Amy looked at her checklist. She still needed someone of this man's age and race.

_This could be interesting_, Amy thought.

Amy added #5891 to her "keep" pile.

* * *

Amy went straight from work to The Cheesecake Factory for lunch, where they had agreed to meet. Her parents had argued that since Amy was always talking about it, the place must be pretty good.

Luckily, Penny had the day off. Amy wasn't quite ready to introduce her mom and dad to her best friend yet.

By the time she got to the restaurant, her parents had already been seated in a booth in the back. Her dad stood up to greet her as she approached the table. With the exception of his tall stature, Amy had been bequeathed with more of his features than she had her mother's. He had brown hair, hazel eyes and glasses, and of course the feature Amy loved the most… his smile.

He was wearing the same old tan blazer with the brown elbow pads that he'd had for years. As soon as Amy reached him, he pulled her into a tight hug.

"Hey, Button," he said. Hearing her childhood nickname made Amy grin from ear to ear. Her father's hugs were one of her favorite things. She felt so safe in his arms.

"Let go, James," her mother said. "I want to say hello, too!"

Her dad finally released her so that her mom could squeeze in a hug. Then, he scooted over in the booth so that she could sit down beside him.

"We ordered you a water… I wasn't sure what you would want," Her mom said.

"Water's fine," Amy grabbed the glass and took a sip out of the straw. "How was the flight in?"

"Oh, it was awful," Her dad said. "Turbulence the whole way… but what do you expect?" He grinned at her.

The waitress came by to take their orders and cleared away the plate of appetizers that her parents had eaten.

"How was work today, Amy?" Her mom had always shown an interest in her career, which Amy appreciated.

"Oh, it went well. I'm finalizing my list of participating subjects. We'll begin calling them in next week."

"Oh, that's great! I hope everything goes smoothly."

"Me too," Amy said then turned to her dad. "So, dad, how did you get a job way over here in California?"

Her dad worked at an advertising company based in Philadelphia. It was rare that anyone was transferred, as they usually just sent their employees on business trips for a few weeks.

"Oh, there were two opportunities that came up. One was in Florida and one over here by you. Wasn't really much of a contest as to which one I would pick." He winked at her. "But I don't really want to talk about work now. I'll get plenty of that this week. Today, I want to hear all about you."

"What do you want to know?" Amy asked, shifting in her seat.

"Well, Button… I understand that I'm no longer the only man in your life."

Amy blushed. She had never discussed Sheldon with her father in detail. Her mom had always asked plenty of questions about her boyfriend, though, and Amy assumed that she had passed the information along to him.

Her mom was on the edge of her seat to see how Amy would handle the conversation.

"I suppose not," Amy said sheepishly. "Sheldon is an important part of my life now, too."

"We're going house hunting tonight," her mom said. "We could go eat an early dinner with you and Sheldon, then you two could come along with us."

_That would be something_, Amy thought. Sheldon, cooped up in a car with her parents all evening. She definitely didn't want their first impression of him to be in a confined space where neither party could escape. Besides, she had only put in the advanced notice for Tuesday night dinner.

Luckily, sensing her unease, Amy's dad came to the rescue.

"Now, Carol, there will be plenty of time for that. We'll meet him soon enough."

Her mom looked deflated.

"Well, he has dinner plans with his friends, anyway," Amy said. Not completely untrue. Of course, Sheldon technically _always_ had dinner plans with his friends. For example, tonight was Monday. That meant it was Thai food night.

Her mother eyed her suspiciously. Amy could sense that she had been expected to confess that the tales of her relationship had been a sham this whole time.

"Well, how about you meet him for yourself tomorrow?" Amy confidently returning her mother's stare. "Sheldon told me he'd be able to go to dinner with us then."

"Sounds great!" Her dad said happily. "I'll certainly want to get to know this man who has my baby girl's heart."

"Tomorrow night it is," Her mom leaned back in her seat. "I saw a lovely seafood restaurant down the road that I'd like to try."

_Oh, boy. This is really going to happen,_ she thought. It hadn't completely set in until this moment.

* * *

After lunch, Amy's parents went to check into their hotel and then begin house hunting, while Amy returned to the lab.

She was a bundle of nerves thinking about tomorrow night's meeting of three of the most important people in her life, and was finding it hard to concentrate on her paperwork.

"You seem distracted," Hannah said as she entered the data into the computer for the subjects they had chosen for the study.

Amy nodded. "Yes, tomorrow evening is kind of an important night."

"What's up?" Hannah asked, her eyebrows arching over her lime green glasses.

"My parents are meeting my boyfriend for the first time."

"Ohhhh… I see." Hannah nodded in understanding. "The _big_ meeting."

"What did your parents think when they met Mark?" Amy asked. She knew that Hannah and her fiancé were going through some sort of rough patch, though she didn't know the details.

"Oh, I remember being so worried the night they met," Hannah said. "But it turned out great. They got along tremendously!"

Amy breathed a sigh of relief. _Maybe it won't be so bad after all_.

"Of course, _his_ parents despise _me_," Hannah added.

Amy's heart sank. "Can I ask why?"

Hannah stopped typing and thought for a moment about Amy's question before answering.

"Well… let's just say, we're _different people_."

_Great_, Amy thought. Sheldon and her parents were about as different as they come.

Just then, her phone buzzed in the pocket of her lab coat. _Speak of the devil_. It was a text from Sheldon.

-_Hi Amy. I have revised the relationship agreement. When would you like to review it?_–

Amy sighed and typed her response.

-_How about tomorrow before dinner? I'll come to your apartment._–

-_That is satisfactory. I'll see you then.-_

Since the initial shock that he would be meeting her parents had worn off, Sheldon - surprisingly - had not seemed too worried about it. Of course, he continued to gripe about having to miss a syndicated episode of Dr. Who on BBC America, but after setting up TiVo to record it, he was relatively calm about the whole matter.

Amy assumed he just didn't understand what the meeting would represent for their relationship, and deduced that his hesitance in the beginning had mainly been due to the fact that it would disrupt his schedule. She was honestly flabbergasted at his lack of concern, especially considering he had made such a scene the first time he had met her mother via Skype a couple of years before.

But even though her boyfriend was being particularly annoying about his television program, Amy was relieved that he at least wasn't stressing out about dinner. She was nervous enough for the both of them, and already knew she'd be getting little to no sleep that night.

She was going to have to have a phone chat with her bestie to settle the butterflies in her stomach before bed.

* * *

**Chapter seven coming soon!**

**Notes:** Reviews welcomed! Thankya in advance! :o)


	7. Chapter 7: The Agreement Alteration

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 7: The Agreement Alteration**

* * *

Tuesday had Amy in a tizzy.

She had barely gotten any sleep the night before. Between thinking about the modified Relationship Agreement and the scheduled dinner that night with her parents and Sheldon, Amy couldn't bring herself to go in to work. She had taken a personal day, and met up with her mother for a morning of house hunting.

It was just the two of them, since her dad had gone in for his first day at his new job.

Most of the places that they looked at were in Glendale, where Amy's family was originally from, and where most of her aunts and cousins still lived. Her mother thought it would be best to be near the rest of her extended family.

"This one's nice," Amy's mother said as a realtor showed her around one particularly roomy place.

"Why do you need three bedrooms?" Amy asked.

"Oh, I don't know… maybe for an office and a guest room," her mom replied. "You could stay over occasionally if you'd like. It would be nice to have the whole family together again!"

Amy smiled at her mom. _When she isn't hammering on about Sheldon, she's actually quite pleasant._

Amy had to agree that it would be a lot of fun to spend major holidays with her parents and her other relatives as she had growing up… and in the same city where she was raised too! Unlike Sheldon, Amy had always enjoyed holidays - even those rooted in religion - as she liked the feeling of family camaraderie.

By the end of the afternoon, the two had found some acceptable options to present to Amy's father.

"I suppose we will have to rent for at least a little while," Amy's mom said while driving back to the hotel. "Buying a house does take time, after all."

Amy agreed. "There are plenty of places to rent around here, that's for sure. You can probably find a pretty nice apartment or townhouse."

"Ugh! I hate renting," her mother groaned.

When they pulled up to the hotel, Amy gathered her things, bid her mom farewell, and hopped in her own car to go home and freshen up before having to leave for Sheldon's place to review the relationship agreement.

After taking a quick shower, she stood staring into her closet for an unusually long amount of time. She just couldn't figure out what to wear. _This is worse than date night_, she thought.

She finally settled on a pale pink cardigan that she had bought with Penny at the mall the week before, and a knee-length denim skirt. After combing her hair to until her arm was exhausted, she pinned it back and looked at herself in the mirror.

"I think this is as good as it gets," she told her reflection. She scooped up her purse and headed out the door.

* * *

Amy arrived at Sheldon's apartment just after 5:00, and knocked on the door. To her surprise, Leonard was the one who answered.

"Oh, hey Amy!"

"Leonard." Amy looked past him into the apartment. "Is Sheldon here?"

"Oh, yeah. Come on in!" He waved her through the door and closed it behind her. Amy meandered into the living room and stood awkwardly by the couch.

"Big night for you two, right?"

Amy nodded. "Yes. My parents are anxious to meet Sheldon… where is he?"

"Well, once I explained the magnitude of what tonight meant for you two, he became rather nervous…" Leonard stared down the hallway. "In hindsight, I probably shouldn't have said anything... He just seemed so unnaturally calm that I wasn't sure he understood what was happening."

Amy groaned and sat down in her spot on the couch. "Great. Now he's probably hiding in his room trying to find some kind of excuse to get out of it."

"No, I don't think so… I think he's back there getting ready."

As if on cue, Sheldon opened his door and walked into the living room.

"Amy! I didn't know you were already here." Sheldon was shifting around uncomfortably in his plaid suit… the same one he wore on special occasions or for important speaking engagements. In his hand he held a stack of papers - no doubt, the updated relationship agreement. As she looked at him, she realized that as everything else was changing in her life with regard to her work and family, she was relieved that she could always count on Sheldon to be... Sheldon. Simple as that.

"I just walked in," Amy said. "You look nice." He did. He looked really good, in fact. She'd always loved that suit on him.

"Well, I've been _informed_ – " He looked at Leonard – "That tonight is rather important."

Leonard shrugged. "Hey, if you didn't want my help, then why'd you ask for it?" He walked over to the door. "I'll leave you two alone. I'll be over at Penny's if you need anything."

After Leonard left, Sheldon took his place on the couch.

"Here you go, Amy. The revised Relationship Agreement for you to review."

Amy took her copy of the document and read through the updated sections, which Sheldon had highlighted.

The first update pertained to handholding.

_-Section 5: Handholding-_

_Handholding is only allowed under the following circumstances:_

_a) Either party is in danger of falling off a cliff, precipice, or ledge._

_b) Either party is deserving of a hearty handshake after winning a nobel prize._

_c) Moral support or comfort in times of immediate emotional or physical distress/need._

Amy read over the change, and looked back at Sheldon.

"Do you approve?" He asked.

The only thing that had changed here was that there would be more opportunity for hand-holding. _Of course I approve._

"I approve," she said out loud.

"Very well. Initial that section, please."

She initialed, and they moved on to the second update… family gatherings.

_-Section 8: Family Gatherings-_

_In the event that either party's family hosts a gathering, rules will be as follows:_

_a) It will be considered mandatory for either party to attend a family gathering or activity no more than once per month._

_b) Either party must provide 72 hours advance written notice of any family-related activity._

_c) Either party reserves the right to spend as much time with their respective families as they desire independently, unless it interferes with a previously arranged date night (see section 3)._

_One night a month?_ With her family being in town indefinitely, they would more than likely want to get together more than that.

"This won't work, Sheldon."

He looked shocked and re-read the document that he had drawn up. "What do you mean? What do you disagree with?"

"My parents will want to see you more than once every four weeks… and what if there are two major functions in any given month? For example, my cousin is graduating in May. What if another one of my relatives decides to get married that same month?"

"Well, that would be unfortunate. You'd have to choose your favorite relative, I suppose." He jokingly smiled down at Amy, but his face quickly turned to a frown when he saw his girlfriend's glare.

"Sheldon, I'm not agreeing to this." She put her pen down.

"Well, then, what do you suggest?"

"I will agree to it being mandatory that either party attend _two_ minor family-related get-togethers a month, with the understanding that _major_ family events like graduations or weddings will always be mandatory... no matter how many fall within a given month."

Sheldon eyed her dubiously. "Define a _minor_ get-together."

"Dinner… movie… hanging out… the like," Amy said. "Oh - and I will only agree to 48 hours advance notice for gatherings. Most people do not plan so far in advance for family activities, Sheldon."

He didn't like it, she could tell. He looked down at her, ready to protest, but she gave him a look that said she wouldn't take 'no' for an answer.

He sighed. "Fine. Let me make the changes." He grumbled as walked to his computer and pulled up the document. After making the appropriate adjustments, he printed it out for them both to initial.

"You do realize that you are making out like a bandit in this deal?" Sheldon said as he handed Amy her copy of the agreement and filed his own away in his desk.

Amy tucked hers into her large purse, and shot him a sly grin.

"Now that that's settled... are you ready to go to dinner?" she asked.

"As ready as I'll ever be," he answered, looking at the floor. Amy was glad that he was finally taking the dinner seriously, but was now concerned that he had become too nervous. She wished that Leonard hadn't said anything._ Who knows how Sheldon will conduct himself under such stress_.

After Sheldon double-checked to make sure that TiVo was set to record, the couple gathered their things and left the apartment.

They walked down the stairs, her shoulder tapping lightly against his. As they rounded the last floor, Sheldon held his hand out to Amy.

Amy looked at it, then back up to him. "Yes?"

"I'm meeting your parents, Amy. This is important. I am in need of comfort."

"Oh. Of course." _On second thought, maybe I should thank Leonard after all._

Her heart skipped a beat as she took his hand in hers. His palm was sweaty, but she welcomed the warmth of his skin. _Why can't we do this all the time?_ She wondered. _He has to realize how great this feels._

They continued hand-in-hand down the stairs and out to Amy's car, letting go only when she had to open her door.

Neither Sheldon nor herself had ever been much for small talk, and Amy had always appreciated the fact that they could sit in silence together. However, there were some moments - like this one - when she wished she could pick his brain and figure out what was on his mind. She wanted to help him relax somehow, or at least offer him some advice to help him get through the night in once piece.

"Sheldon, I should warn you about my mother," she stole a quick glance in his direction. He kept his eyes straight ahead on the road in front of them. "She can be a bit nosy... but she doesn't mean anything by it."

Sheldon nodded. "I'm used to nosy people. I live next door to Penny," he said as Amy pulled the car into the restaurant parking lot. _He has a point._

She noticed that Sheldon had begun to visibly perspire.

Amy didn't blame him - she was just as nervous. She wasn't sure how her parents would react to her boyfriend, or how Sheldon would handle the situation. Both sides would be looking to her for direction on how to proceed.

She took his hand again as they walked quietly from the car to the restaurant, the loose gravel of the parking lot crackling under their shoes.

Her parents were already there, leaning against a wall waiting to be seated. When her dad saw them, he took two big strides their direction and ended up right in front of Sheldon.

"Sheldon Cooper, I presume?" Her father extended a large hand to him.

Sheldon stared at it... frozen.

_Oh dear_.

* * *

**Chapter eight coming soon!**

**Notes:** The big meeting is next! I'm almost as nervous as Amy and Sheldon! :o) Please review!


	8. Chapter 8: The Introduction Tension

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 8: The Introduction Tension**

* * *

"I'm Amy's father, James." Amy's dad still had his hand out waiting for Sheldon to take it.

Her boyfriend studied the man's hand for a moment, unsure, then - after a nonchalant nudge from Amy – he reluctantly stuck his own hand out and placed it in her father's palm.

Her dad shook Sheldon's hand so hard that Amy was afraid his wrist would break.

When he finally released him, Sheldon wiped his hand on his pants. He tried to do it discretely, but it didn't go without notice by Amy's parents. They both eyed him suspiciously.

"Mrs. Fowler." Sheldon said, with his hands firmly clasped behind his back.

"Hello, Sheldon." Amy's mom said. "Good to finally meet you_ in person_."

Sheldon looked at Amy. She knew he would be relying on her for social cues. Amy nodded at him.

He immediately nodded back at Amy's mom.

"Shall we?" Her dad motioned toward the hostess counter, and they were promptly seated.

Sheldon slid into the booth next to Amy, and swiftly grabbed her hand under the table. Amy couldn't help but smile to herself, even though she knew the gesture was just a sign that he was nervous about the evening.

Before they could even get settled in, the waitress came by to take their drink orders.

"So, Sheldon," her dad began, once the waitress had left. "I want to know all about you."

"Well, that would take quite awhile," Sheldon said matter-of-factly. "I don't think we have that kind of time."

Amy's dad gave a loud laugh.

Sheldon looked surprised at his response, as he hadn't intended it as a joke - but then shot a breathy laugh back toward James.

"Well, just the highlights, then, my boy." James continued. "Tell me about your work."

"I'm a theoretical physicist at Caltech… with a focus on M-Theory. I'm on a trajectory to win a Nobel Prize for my work sometime in the future."

"Wow. That's quite an accomplishment," her dad said. "Sounds like my Amy chose her man wisely."

Amy blushed and looked down at Sheldon's fingers entwined in hers.

"Amy is more similar to me that anyone I know," Sheldon said without missing a beat.

Amy gazed up at her boyfriend. _He really is like a sexy praying mantis._

Her mom looked just as shocked as her daughter that Sheldon was actually pulling this off.

"We'd better decide what to eat," Amy said, looking down at the menu. Sheldon had never eaten in this particular seafood restaurant, so Amy knew that there would most likely be trouble when it came to ordering. She wanted to give him the most time possible to figure it out. They perused their menus in silence until the waitress stopped by again.

"Do you know what you'd like to order, or do you still need a few minutes?"

They all nodded that they were ready and the waitress jotted down their orders. Amy's parents both ordered lobster, and Amy chose salmon. Then, it was Sheldon's turn. Amy held her breath.

"Do you have hamburgers?" Sheldon asked.

The waitress and Amy's parents looked surprised at his choice. Amy, however, did not.

"Um… yes. We do, actually. It's on the kid's menu, though."

"What makes it a 'kids' burger?" Sheldon inquired.

"I dunno… its… small, I guess?"

"Well, do you have another burger to compare it to?"

"No. We don't have burgers on the regular menu."

"Then, wouldn't you just say 'this is our burger'… rather than make it a 'kids' burger?"

The waitress just stared at him, dumbfounded.

Amy kicked Sheldon under the table.

"Ow!" he said, looking down at her.

"Just get the burger, Sheldon," she said

"Fine," Sheldon said, looking back at the waitress. "I'll take a hamburger with no tomato. Do your hamburger buns have sesame seeds?"

"No."

"Ok, good."

"Alrighty, sweetheart," The waitress said. "You want fries with that?"

"Are they curly fries?"

"No."

"Then, no. What else do you have?"

"Umm…. We have salad, mashed potatoes, green beans, mac and cheese…"

"None of those options seem agreeable."

"Well… that's all we have." Her frustration showed on her face.

"Do you have any fruit?"

"We have a melon bowl."

Sheldon scrunched up his nose. "No apples or mandarin oranges?"

"No."

"Very well. I'll have nothing."

"Just the burger?"

"Just the burger."

"Ok." She scribbled something on her pad, took their menus, and walked away.

Amy's parents were staring at Sheldon like he had just cut off his own ear.

Amy quickly tried to change the subject.

"Umm… dad," Amy started. "How was your first day at work?"

James shook the confused expression off his face and turned to his daughter. "It was fine. Mostly just getting settled in. You know how it is on those first days."

Amy nodded.

"So, Sheldon?" Carol asked, still staring at him like he was from outer space.

Sheldon looked up at her.

"It's been a long time since I talked to you last."

_She would keep trying to bring this up,_ Amy thought. _She can't let that Skype session with Sheldon go._

"Have you and Amy been… active… this whole time?"

"_Mom_!"

James choked on his drink.

Sheldon looked surprised. It was clear he didn't understand the reference.

"Mom, that entire conversation was a fabrication. None of it actually happened!" Amy argued.

"Yes, but you say you are actually dating _now_. So, one can only assume - "

"No, mom," Amy interrupted.

"Let it go, Carol," James whispered to his wife.

Sheldon still looked just as confused as before. _Thank goodness he isn't grasping this_, Amy thought.

Amy's mom shrugged, still unsatisfied with her daughter's response, and took a sip of her iced tea.

"What kind of car do you drive, Sheldon?" Amy's father was desperate to move on to another topic… any topic.

"I don't," Sheldon said.

"I'm sorry?" James looked at Amy and then back to Sheldon. "What do you mean?"

"I don't drive," Sheldon admitted.

"Sheldon has _chosen_ not to drive," Amy butted in. She glanced at her boyfriend before continuing. "He finds it saves money, and is less stressful. He takes the bus or carpools."

"Ah." James said, "Well, are you a sports fan, Sheldon?"

"No."

"Oh." Her dad seemed disheartened. _He truly is trying to connect on some level with Sheldon, _Amy thought. She had to help him out.

"Sheldon develops his own board games", Amy said.

"Oh?" Her dad's interest was peaked. He loved board games, and was especially good at chess. During the course of his career in advertising, he had worked with various entertainment and gaming companies. They were his favorite clients.

"Yes," Sheldon said. "I developed a physics-based game called Research Lab, and also created a three person version of chess."

"Really? That's amazing!" Her dad was genuinely interested.

"Yes. I invented several additional chess pieces as well."

"Have you played the game, yet?"

"I played one initial round with some friends of mine just to test the game play, but nothing too in-depth."

"And?"

"I'm still working out some kinks, but it the basic layout is strong."

"Well, now, that's something I would like to see. We should play sometime."

Sheldon smiled. He was pleased that someone seemed so interested in a project that he put so much effort into. "Sure! We'll have to arrange that."

Amy was impressed. Sheldon wasn't doing as poorly as she thought he would. In fact, when they were on the right topic, he was managing quite well!

The waitress returned with their orders, still wearing a puzzled expression when she set the children's burger down in front of Sheldon.

As her parents broke into their lobster, Sheldon doctored his burger to his specific requirements… sprinkle of pepper here, dash of mustard there. Amy's mom watched in him fascination.

Eventually, Sheldon was ready to eat and Amy felt obligated to pick up the conversation that had dropped away with the arrival of their meals.

"So, mom, did you show dad the houses we looked at earlier today? Have you two decided on anything yet?"

Carol shrugged. "We've made progress. We haven't agreed on a house that we would like to buy yet, but we did start looking around online for a rental just before dinner. Obviously, we wouldn't want to rent for long... but a couple of months would be okay."

Amy nodded. "Makes perfect sense. Where have you looked?"

"Here and there," she said. "No place in particular. We'll know it when we see it. I'm sure we will have a place picked out by the time I return to Philadelphia on Saturday."

Carol took another bite and looked as if she was really pondering something. "Amy?"

"Yes?"

"We'd like to see _your_ apartment sometime."

"Of course." Amy said, forking a piece of salmon into her mouth.

Her mom peered at her above her glasses. "So… you do still have your apartment? You're still renting?"

Amy was confused. "Of course… Why wouldn't I be?"

Carol looked over at Sheldon, who was devouring his burger, then back to Amy. "Well… I know how it is… you know… with young couples these days."

It took a moment before Amy picked up on what her mother was implying. As the realization sunk in, her jaw dropped in shock. "Mom. Seriously! How long have you known me?"

"Honestly, Carol," Her dad inserted. "Couldn't we discuss things like this with Amy _privately_."

"Sheldon doesn't seem bothered with it." Her mom motioned to him. At the mention of his name, Sheldon looked up.

"Why would I be offended by Amy's rental status?"

"Well, regardless," her dad said. "_I'm_ uncomfortable."

Carol sighed and ate the rest of her meal in silence. Amy was practically fuming inside until she realized that she _had_ almost moved in with Sheldon not long before. That is, until he put a stop to it. Her mother didn't need to know that, though.

When the time came to pay the check, James and Sheldon both reached for it.

"No, no," James said. We are taking you two out this evening. You won't be paying."

"But it makes sense for us to split it," Sheldon argued.

"Nonsense."

Sheldon wasn't pleased. Amy knew he didn't like feeling indebted to anyone else, least of all her family. Amy took his hand again under the table and squeezed it.

He looked at her and she saw his shoulders relax… the tension melting away.

"Very well," Sheldon surrendered.

"Thank you, Dad," Amy said.

"Don't mention it," He winked at her.

The group gathered their belongings and left the restaurant together. They walked through the parking lot in silence, until Amy reached over and gave her dad a hug goodbye.

"I'll see you later this week, Button," he said. Amy smiled and moved to her mother. The tension still hung between them as they hugged each other.

"You know I love you," her mom muttered in her ear. Amy nodded and pulled away.

She turned back to Sheldon in time to see her dad whispering something to him. Sheldon's face was unreadable, but he looked at her dad and nodded, then the two shook hands. Sheldon barely even flinched at the her dad's touch.

_What was that about?_ Amy thought.

* * *

**Chapter nine coming soon!**

**Notes:** Thank you all for the wonderful reviews so far, they are very much appreciated. This meeting is only one of several important steps for Sheldon and Amy in my story, so I hope you keep following and keep reviewing! :o)


	9. Chapter 9: The Uncalculated Addition

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 9: The Uncalculated Addition**

* * *

As Amy and Sheldon drove home from dinner, Amy quietly stole glances at her boyfriend.

He seemed to be in quite a happy mood after the little chat he'd had with her father. She had hoped that he would have immediately mentioned the encounter once they were alone in the car, but he'd spent the whole time staring out the window at the traffic instead.

He was going to need some nudging.

"So, Sheldon," she began, "What did you think of my family?"

"Oh, they were quite pleasant. Your father, especially."

Amy grinned. Her mother had been a bit obnoxious, but thankfully Sheldon hadn't noticed. She was very happy that he and her dad had gotten along so well.

"Yes… you two were really hitting it off…" Amy pushed.

Sheldon just nodded.

_I can see I'll have to be blunt._

"So, what were you two discussing in the parking lot?"

Sheldon turned to her, his face unreadable once again… just as it had been when she caught her dad whispering in his ear.

"I think I'd rather not say, Amy."

"Oh... ok," Amy sank back into the drivers seat. _Maybe my dad asked him not to say anything._

"Is it a secret?" she asked. _He hates keeping secrets._

"Well, for now anyway. Please don't push me on the matter, Amy."

She couldn't hide the fact that she was hurt by his lack of openness. But, then, Sheldon wasn't one for picking up on others' emotions. He turned back to the window, unfazed by Amy's disappointed reaction.

_What could my dad possibly have said?_ She made a mental note to bring it up with her father later.

"It's still rather early, Sheldon, do you want to go get some dessert or something?"

"No. I don't think so. I'd rather just go home."

Amy just nodded, feeling a little rejected. While waiting at a red light, she took the opportunity to text Penny.

-_Confusing night… are you at home?-_

She set the phone in her lap when the light turned green. Penny finally texted back just as Amy pulled up to Sheldon's apartment complex.

-_Yup! I'm here. Come on up when dinner is over!-_

Amy breathed a sigh of relief. She was dying to discuss the night's events. She parked the car, turned off the ignition, and unbuckled her seatbelt.

"What are you doing, Amy? I didn't invite you in."

She frowned at the confused expression on his face."I'm _aware_ of that, Sheldon. Penny has invited me over."

"Oh."

They both got out of the car, and headed to the door. As they began walking up the stairs, Amy reached instinctually for Sheldon's hand. Her boyfriend briefly wrapped his hand around hers… then immediately loosened his grip.

"What are you doing?" he asked.

Amy looked down at their hands. _What am I doing?_ "Umm… I'm not sure. Holding your hand, I guess."

"Why? Are you in distress?" He looked worried.

She'd become so used to holding hands that evening, that she had forgotten the reason that they had been doing so - the new Relationship Agreement.

"No. I guess not." Amy released his hand, and they continued up the stairs in silence.

When they reached the fourth floor, Amy immediately began walking toward Penny's apartment. Before she reached the door, Sheldon called out for her.

"Amy?"

She turned around to face her boyfriend, who was fumbling with his keys, but hadn't opened his door yet.

"Yes?"

"Thank you for tonight," he said. "I had a really nice evening."

"Me too, Sheldon."_  
_

They stood for a moment looking at each other, each on opposite sides of the hall.

"Do you think your parents liked me?" he asked.

"I think they did," she smiled.

"Good," He sighed in relief. "Good night, Amy."

"Goodnight," she replied. Sheldon turned to open his door.

Her boyfriend slid into his apartment, and Amy knocked on the door of 4-B. Penny answered with a cheerful grin.

"Hey Ames!" She practically pulled Amy inside. "Tell me all about it! Did your whack-a-doodle boyfriend behave himself?"

"Oh, yes. As good as could be expected."

She filled her friend in on all the details of the evening, including the incident with her dad as they were leaving, and Sheldon's reluctance to discuss it.

"That _is_ strange." Penny said. "Maybe he was giving him 'the talk'."

"The talk?" Amy asked.

"You know… the 'don't hurt my daughter or I'll come after you' talk." Penny explained.

"Oh. I doubt that." Her dad wasn't prone to violence, even in the form of an empty threat.

They spent the rest of the evening hypothesizing as to what the "whisper" could have been about. Penny's theories ranged anywhere from murder plots to planning Amy and Sheldon's wedding… each idea more ridiculous than the one before.

Eventually, Amy yawned and decided to go home for the night. She had work in the morning, after all.

"I wouldn't worry too much about it, Ames." Penny said as she showed Amy to the door. "I'm sure Sheldon will tell you when he's ready. I would just focus more on the fact that they managed to get along! That seems to be the most important take-away from the evening."

Amy nodded. _She's right, of course._

"Thanks, bestie," Amy smiled. "You always know just what to say."

Penny shrugged and opened the door. "I may not be book-smart, but when it comes to stuff like this, I like to think that I know what I'm talking about."

"Yes," Amy agreed. "It's a wonder you aren't married yet."

Penny pursed her lips uncomfortably. "Er… yeah."

* * *

The following days passed without mention of the dinner by Amy's parents or Sheldon. She had been so busy at work that she hadn't had many opportunities to really speak with her mom and dad again other than a few brief phone conversations.

On Friday, Amy went straight from work to Sheldon's apartment after receiving a rather pushy call from her frustrated boyfriend asking her to take him to the comic book store. Apparently, Leonard was out on a spontaneous date with Penny and could not drive him as he'd originally planned. Amy wasn't sure of the details, but she knew Leonard could expect to be yelled at later... and would most likely be facing a strike.

It had been a long day at the university for Amy. She hauled her tired legs up the stairs to Sheldon's apartment and knocked on the door.

"Hello, Amy!" Sheldon said enthusiastically as he opened the door. He was always so excited on new comic book night. Amy couldn't help but return his broad smile.

"Are you ready to go?" She didn't even have to ask. He already had his jacket on, and his bag was slung across his chest.

He nodded and switched the light off, closing the door behind him.

"I thought new comic book night was on Wednesdays?" Amy questioned as they began walking down the stairs. "Why are you going tonight?"

Sheldon smiled at his girlfriend. "I'm surprised you remember that, Amy. Good girl!"

Amy smiled back at him. _Of course I remember. I remember everything about you._

"There was a shipping mistake and Stuart got in some of next week's issues early," Sheldon explained. "Leonard and I had planned on going together, but he managed to find a loophole in the Roommate Agreement that allowed him to back out of his obligation to me. " He grumbled and looked away.

"Well it's no problem for me to take you, Sheldon," Amy insisted. "However, I won't be able to stay too long tonight. I promised my parents I would meet up with them for dinner. My mother is leaving for Philadelphia tomorrow to finish up their packing."

Sheldon nodded. "I wouldn't be able to spend a lot of time with you when we get back anyway. I'll be reading my new comic books and I won't want to be distracted."

Amy figured as much.

"Did your parents find a place to rent?" He asked as they stepped into the lobby.

"Yes, they are moving in tonight. They invited me over to see it after dinner," Amy paused. Despite her better judgment, she went ahead and asked her next question. "You're welcome to come with us… if you'd like?"

Sheldon looked down at her with exasperation. "Now, Amy, I just told you I would be reading my comic books. Why would I buy them and not read them immediately? That defeats the purpose of new comic book night."

Amy nodded. She had expected it, of course. She wasn't too disappointed.

"Besides," Sheldon continued. "You didn't provide me with the required notice."

They'd reached Amy's car. "As always, Sheldon, your logic is incontrovertible."

Sheldon grinned and opened his door.

* * *

Sheldon was like a kid in a candy store at Stuart's shop. He quickly moved from bin to bin, and within twenty minutes had a stack of about five comic books in his arms to buy.

While Sheldon perused, Amy chatted with Stuart. She had gone out on a few dates with him before Sheldon had officially asked her out. While Stuart ultimately wasn't the man for her, he was still a great guy in Amy's opinion. She probably owed him a thank you, as it was possible that she wouldn't have a boyfriend today if it weren't for him.

"So, Amy," Stuart asked. "How have you and Sheldon been?"

"Oh, better than ever," she replied, looking over at her boyfriend.

"Well you both look happy," Stuart studied Sheldon. "Of course, Sheldon always looks happy when I get the new issues in."

"Yes," Amy concurred. "It still escapes me how a grown man can have such a child-like obsession."

She glanced over at Stuart, who was pulling a brand new Ironman helmet out of a shipping box.

"No offense," Amy added when she realized she was talking to a man who owns a whole store dedicated to such obsessions.

"None taken."

Amy looked back over at Sheldon. She and Stuart both waved when he looked their way.

Sheldon froze for a moment, then moved swiftly to Amy's side, standing much closer to her than he normally would. Amy didn't mind. She liked it when he got a bit jealous. _He can be so possessive. S_he grinned to herself.

"Hi Stuart." Sheldon said.

"Oh, hey Sheldon," Stuart replied in his typical, doleful voice.

The three stood there a moment, awkwardly looking at one another.

Stuart broke the silence and pointed at the comics in Sheldon's hand. "Do you want me to ring those up for you?"

Sheldon handed them over. "Yes."

Amy smiled up at her boyfriend, and decided to take a risk. She grabbed hold of his hand.

Amy fully expected him to pull away, but - to her surprise - he allowed it. Without flinching, he wrapped his long fingers around hers and held on to her tightly.

* * *

Sheldon made no mention of the hand-holding while they were on their way home. He was too busy going into the elaborate background story lines of all the comic books that he had just purchased.

When they arrived at Sheldon's apartment, Amy decided to walk with him to his door so that Sheldon could finish what was starting to seem like a never-ending monologue about the history of The Flash... or Green Lantern... or whatever superhero he was rambling on about. Amy was only half-listening while Sheldon's arms flew around wildly. Unlike his physics work, Amy had little interest in science fiction or fantasy characters.

_He's so cute when he gets excited, though_, Amy thought.

They walked through the lobby and into the stairwell with a very animated Sheldon still very much involved in his story. They were halfway up the first flight of stairs when his tale was interrupted by a familiar voice.

"Amy?"

Amy turned around and peered down the staircase.

Standing in the lobby were her parents. They had just walked in the door.

"Mom? Dad?" Amy asked, confused. "What are you doing here?"

She trotted back down the steps toward them.

"We are renting a place here. What are _you_ doing here?"

"You're renting _here_?!"

"Yes. We paid our deposit yesterday. We're in 2-A. Right up the stairs there." Her dad pointed in the direction of the stairwell. Amy turned around to follow his finger and noticed Sheldon was gone. She'd worry about him later.

"You didn't answer _our_ question, Amy," her mother said.

Amy turned back to face them. "This is Sheldon's apartment building. I was visiting with him for awhile until it was time to meet up with you for dinner."

"You're kidding!" Her mom said. Her eyes narrowed and she looked around the lobby as if she was going to find something incriminating.

Amy glanced around the lobby too. There were several boxes with her parent's names on them. They must have been shipped in from Philadelphia. _Had these been here earlier? _She hadn't noticed.

"He's on the fourth floor," Amy said, still looking around at the boxes.

"Well, isn't that the most bizarre coincidence?" James said in amazement.

"Well, then, Amy... maybe you can answer a question for us," her mom said. "Why doesn't the elevator work?"

* * *

**Chapter ten coming soon!**

**Notes:** Sorry it took me so long to update this go-around. Work was insane this week! As always, reviews and constructive criticism are welcome! :o)


	10. Chapter 10: The Initial Connection

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 10: The Initial Connection**

* * *

Amy's mom returned to Philadelphia early Saturday morning.

Amy spent the rest of her weekend in between Sheldon's apartment and her parents' new place down on the second floor.

She was doing her best to honor the Relationship Agreement in regard to family gatherings, but even Sheldon acknowledged that it was a problematic endeavor. With her parents living in the same building as him – even for a short period of time – it was inevitable that they would be seeing more of each other than Sheldon and Amy had planned.

On Sunday evening, Amy had talked Sheldon and Leonard into venturing down to help her dad mount his new television on the wall.

"I don't see why I am coming," Sheldon said as they made the short journey down the stairs. "We all know that Leonard's the muscle."

"Yes, Sheldon, but he's _your_ girlfriend's dad," Leonard said. "You need to be there too. It's socially appropriate."

"Oh… '_It's socially appropriate_'..." Sheldon mocked. "You know, Leonard, sometimes I think that you all take advantage of my lack of familiarity with social conventions and throw that phrase around just to get your way."

Leonard and Amy rolled their eyes as they reached her parents' apartment. Amy let herself in, and led the boys inside.

She introduced Leonard to her dad right away. As James shook Leonard's hand he paused and his face brightened.

"Wait… Leonard?" Her dad asked.

"Yes, sir." He said, still holding onto his hand.

"I know you. You were with Amy at one of the family weddings."

Leonard smiled. "That's right! I believe I did meet you there."

James laughed and let go of Leonard's hand. "Yes, I definitely remember. You and Amy were cutting a rug on the dance floor. You kids were having a blast, it looked like."

Leonard laughed back. "Yeah, it was a lot of fun!"

"You'd better watch out, Sheldon!" Amy's dad joked, elbowing Sheldon's side. "Leonard here might give you a run for your money with my Amy!"

Sheldon looked horrified. He caught Leonard's eye and glared at him. Sheldon, Amy surmised, had never been told much about what happened that night.

Leonard coughed nonchalantly and changed the subject. "So… James… where's this TV that needs mounting?"

James escorted Leonard and Sheldon to the other side of the living room, where a mounting system was sprawled in pieces on the floor.

Amy collapsed into the couch with her laptop while they hung the TV. About an hour later - and without much help from Sheldon - it was finally attached to the wall, albeit a little crooked.

"Honestly, Leonard... you call yourself a physicist," Sheldon shook his head. "You can't even mount a television at the proper angle."

"Aww, it looks fine. Not too noticeable," James said, patting Sheldon and Leonard on the back. Sheldon winced.

"Well, I've got to be getting back," Leonard said. "I promised Penny I would run by her place tonight."

"Of course," James said. "It was good to see you again, Leonard. Thanks for your help!"

Leonard waved and headed out the door.

Amy stood up from the couch. She stretched and walked over to give her dad a hug. "I should be going too," she said. "I have work in the morning."

She and Sheldon headed for the door, but as they went to leave, James stopped them.

"Sheldon?"

Sheldon was already halfway through the doorway behind Amy, but he turned back to James.

"Do you mind if I talk to you for a moment?"

Amy looked back in confusion, but she looped around to follow Sheldon as he stepped back inside the apartment.

"Oh, no Amy. I don't want to keep you. You can go ahead and head on home."

Amy glanced from her father to Sheldon… she wanted to ask what was going on, but could tell by Sheldon's expression that he wouldn't answer.

"O… K… " Amy said, "I guess I'll see you tomorrow, Sheldon?"

She glanced up at him uncomfortably.

"Oh!" James said. "I'm sorry. Let me give you some privacy." He scurried away to the kitchen, which – in all honesty – wasn't much more private than him being in the living room.

"Um…" Sheldon looked down at Amy, unsure of what James was presuming they would want to do that would require seclusion.

Her dad obviously hadn't picked up on the unique nature of their relationship yet. However, as Amy's dad was still technically in the room and was apparently expecting some sort of physical display, Sheldon reached his arm out and awkwardly put it around her shoulders, pulling her slowly into a hug.

Amy's heart stopped the moment he touched her. As she leaned into her boyfriend it kick-started again, beating unbelievably fast.

The hug probably lasted only half of a second, but it was enough to completely throw Amy for a loop.

They let go, and she took a clumsy step backward into the doorway.

"Umm… Bye, Sheldon."

"Bye, Amy."

She pulled the door closed behind her and headed home.

* * *

The next day, Amy was all business. As much as she wanted to, she didn't have a lot of time to think about Sheldon and her dad.

She and Hannah had begun calling in the subjects for their study.

They brought them in, one by one, and hooked them up to the electrodes to monitor their brain activity. These initial observations were just control tests, so they were asking simple questions.

"This is going quite smoothly," Hannah said, relieved, after their sixth subject of the day had left the room.

"Did you expect there to be any issues?" Amy asked.

"Well, no, but you never know with these kinds of things. I'm surprised we are getting as good of readings as we are... considering we don't have an f-MRI. I was really hoping the university would splurge and allow us to bump the quality up a notch."

"You know how these grants work," Amy said. "We're just lucky to get to do it at all."

Hannah nodded. "I suppose you are right."

They called their next subject in.

Amy looked up as a tall, thin man wearing tight denim pants and a plaid button-up shirt stepped through the door. He was slightly tan and had blonde, shaggy hair.

The man muttered to himself as he walked toward the table where Amy and Hannah were sitting. It was only as he got closer that Amy could make out what he was saying.

"13…14…15…" He stopped at the table and gave them an uneasy look. Then he squeezed in one last tiny step between himself and his chair. "16," he said. Then, he pulled out the chair and took a seat.

Amy realized he had been counting his steps to the table. _Obsessive Compulsive Disorder_. She looked at her chart. He was #5891.

"So," Amy started. "We're just going to hook these up to you, so that we can monitor your brain activity." She motioned to the equipment on the table.

He nodded. "Ok."

Hannah began hooking up the electrodes. He grimaced and stiffened as she touched him. Amy knew from dealing with Sheldon that this man would need something to distract him from what Hannah was doing if he was going to relax at all.

"Thank you for helping us out with our study," Amy said. His eyes met hers. "Today will be relatively easy, so there's no need to worry. We will just be asking basic questions. It shouldn't take any longer than 20 minutes."

He nodded again and shifted in the chair.

"Hopefully, the data that you provide us will help us with our research," Amy continued. "We're lucky that we've had such a good response from people like you who have been willing to participate."

His shoulders relaxed a bit and the corners of his mouth curled up in a slight smile. "I do what I can," he said.

Amy studied him as Hannah finished attaching all the wires.

He looked nothing like Sheldon. The two were about the same height and build, but this man was definitely less pale. His blonde hair kept falling across his forehead and into his eyes, forcing him to occasionally brush it away.

Still, Amy was entranced by how much his mannerisms reminded her of her boyfriend. Though he had calmed a little, he was still very tense and noticeably uncomfortable with this whole process.

Once everything was in place, Hannah sat down next to Amy and picked up her clipboard to begin asking questions.

"State your name."

"Ben. Well, Benjamin… but people call me Ben."

"Ben works. How old are you, Ben?"

"30."

"Where are you from?"

"Los Angeles."

Amy monitored his brain activity and took notes, while Hannah continued with her questioning. Amy could feel Ben watching her throughout the process.

"What is your profession?"

"I'm a Chemistry professor, but I also write books.

Amy looked up at him. She didn't take him for the writer type.

"Chemistry books," he added, when he noticed her curious expression. "Mostly for educational purposes."

"Are you married?" Hannah asked.

"No."

"What about children? Any kids?"

"No."

Hannah proceeded through several pages of the questionnaire. When the form was finally complete, she put down her clipboard.

"Well, that's it, Ben! We told you it'd be painless."

He gave a weak laugh.

As Amy began taking the electrodes off his skin, Ben looked up at her.

"You smell like coconut."

Amy was taken aback. "What?"

"You smell like coconut. I'm sorry… was that inappropriate to say? I wasn't trying to sound forward or anything. I was just stating a fact."

"Oh, no… that's fine. I just wasn't sure I heard you correctly," Amy said. "Thank you, I guess?" She didn't know if it was meant to be a complement.

Ben nodded. "It's definitely a good thing. I'd rather work with someone who smells like coconut than someone who smells like lavender. Lavender tends to make me sleepy."

"That makes sense," Amy said as she finished putting away the equipment.

"What's your name?" Ben asked.

"Amy. That's Hannah," she pointed at her coworker.

Ben didn't look. Instead, he rose from his chair and scanned Amy up and down. Their eyes locked, and for a moment they just stared at each other.

_He's so much like Sheldon, _Amy thought.

Suddenly, Ben crossed his arms over his chest and turned to Hannah.

"I assume you will call me when you need me in again?"

Hannah had been watching the exchange between Ben and Amy in awe, so was startled when he finally addressed her.

"Oh… yes. We will call you," Hannah said. "Thank you."

Ben nodded at her and then to Amy before walking out of the room, counting his steps under his breath.

Amy watched until the door closed behind him, and then began rustling her papers around on her clipboard, looking for the next subject's paperwork.

"What was that about?" Hannah asked with a smirk.

Amy stopped rustling and looked up at her partner confused. "What do you mean?"

"What do you mean '_what do I mean'_?" Hannah exclaimed. "I felt that tension between you two way over here!"

Amy turned red and began sifting through her papers again. "I don't know what you are talking about. It was just chit-chat. It's good to build a positive rapport with the people you will be working with."

"Ok… sure," Hannah said with disbelief, nudging her cherry-colored glasses up her nose. "You _really_ made an effort with that girl that came in before him."

"I have a boyfriend, Hannah," Amy insisted. "I don't know what you thought you saw."

"Well, that hasn't stopped people before," Hannah argued. "Besides, Ben doesn't know you have a boyfriend. To him, you're free game."

"First of all, Ben is a test subject. We aren't allowed to socialize with them outside of the study. Secondly, I am not like _those people_ you are talking about. I have a boyfriend, and that means something to me. I love Sheldon. I wouldn't ever cheat on him."_  
_

Hannah's eyes became distant, and she quickly looked down at her clipboard.

"You're right. I'm sorry I insinuated it," she said. "Who's next?"

Amy could tell she was trying to change the subject, which Amy fully supported. She was glad to move on.

"Number 7810 is next," Amy said. "I'll go call him in."

Hannah silently nodded, but didn't look up from her clipboard.

* * *

**Chapter eleven coming soon!**

**Notes:** Ok, once again, I feel I must state that I am not a neurobiologist, nor do I have much understanding of the field. Any discrepancies found in this writing with the way that actual research is conducted is just ignorance on my part, pure and simple. Don't hate me for it, please. :o)

I'm trying to update as often as possible - but so far this week has been ridiculous at work. I've worked almost 24 hours a day for the past two days. Utter nonsense, I say.


	11. Chapter 11: The Paranoia Factor

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 11: The Paranoia Factor**

* * *

"How is your study going, Amy?"

It was Wednesday, which meant Sheldon was getting ready for Halo night. Leonard had left to get the pizza, and Amy was relaxing in the armchair while Sheldon prepped the video game system.

"Oh it's going just fine so far," Amy answered. "We've been meeting with our test subjects this week. They've all been working out quite well."

Sheldon contorted his face in disgust. "I would never be able to participate in a study like that. I don't see how people could willingly submit themselves to being prodded and probed."

Amy rolled her eyes. "We aren't extra terrestrials, Sheldon. I'm not going to be probing anyone."

"Still," he said as he unraveled the cables on the PlayStation, "It _is_ a shame that more people of _our_ mental caliber don't participate in those studies. You'd probably get better results."

"What makes you think they don't?" Amy laughed to herself. _If only he knew how alike he and Ben are._

"Because as a rule, studies like yours are meant to show the results based on data representative of the populous as a whole. You and I, Amy, are superior beings. Your candidates are probably all woefully uneducated, aren't they?"

"Our candidates are just fine, Sheldon," Amy said. "We are just getting started, of course. We will begin the truly interesting part of the study in a few weeks."

Sheldon shrugged. "You and I differ somewhat in our definitions of 'interesting', I believe."

"Clearly." Amy rebutted. "_I_ wouldn't spend an entire evening playing nonsense video games."

Sheldon stood up and turned to her with a grimace. She just grinned mischievously back at him. He was cute when he was all riled up.

He took a deep breath. _Kohlinar_, Amy assumed.

Sheldon finally opened his eyes when there was a knock on the door. Before he could answer it, Howard and Raj popped in carrying several plastic bags filled with snacks.

"We have beer!" Raj shouted. He looked over at Amy. "Not that we need it, though!" He winked at her.

Amy snickered. Raj never missed an opportunity to point out that he was no longer hindered by his selective mutism.

"You didn't tell us Amy was going to be here," Howard said to Sheldon. "I would have asked Bernadette to come."

"I'm not going to stay," Amy said before Sheldon could respond. "I'm actually meeting up with Bernadette and Penny for a girls' night."

"And you call my video games nonsense," Sheldon said with an eye roll.

Amy ignored his comment, and stood to leave. "Goodbye, Sheldon… boys."

Everyone waved to her as she walked out the door.

* * *

Amy, Penny and Bernadette had decided to have a subdued girls' night, as it was a Wednesday and they all had to work in the morning.

They ended up just going out to eat and catch up.

"I swear my understudy is trying to take me out," Penny leaned over her plate of fettuccine alfredo and whispered, as if she was divulging top-secret information. "The other day, I caught her with what appeared to be a vial of something. And she's always just… _there_. Ya know? Like, I'll come out of the bathroom and she'll be there, or I'll turn around in the hallway and – _bam!_ - there she is."

"If she so much as touches you, I'll take her out," Bernadette threatened. "I have access to all kinds of virulent materials. She wouldn't know what hit her."

Based on the look in Bernadette's eyes and the death grip she had on her fork, she was serious. Penny leaned back with a scared expression on her face.

"Well… I mean… don't do anything crazy," Penny said. "I don't have any proof yet."

"You know, bestie," Amy offered. "It's possible you are suffering from simple paranoia. I'd refer you to a therapist, but most people with the disorder refuse to be treated with therapy. Studies show that the paranoid brain has difficulty opening up to another person, as the individual doesn't believe that they have a problem. So, I'm not sure a recommendation would do you any good."

Penny rolled her eyes. "I don't need a therapist."

Amy nodded. "See?"

Penny groaned and changed the subject.

"Speaking of _paranoid_… did you ever figure out what your boyfriend and your dad were conspiring about?"

Amy frowned. "No. Sheldon won't tell me. I've asked him a few times, but he keeps brushing me off."

"You should ask your dad," Bernadette said, taking a big bite of spaghetti.

"I know. I haven't had a lot of time to talk to him, though."

"Well, your boyfriend certainly has," Penny said, slurping up a piece of pasta.

Amy's eyebrows scrunched in confusion.

"I've caught Sheldon going in and out of your dad's apartment a couple of times," Penny explained.

"Really?" Sheldon hadn't mentioned that he'd been having any additional chats with her dad.

"You should just stop in and ask your dad what's up," Bernadette said.

"Yeah, I'll drop by his place tomorrow on my way to Sheldon's apartment."

Amy looked up and noticed that Bernadette had her eyes fixed on something behind her. "Can we help you?" Bernadette asked.

Amy turned around to follow her friend's gaze.

"Ben!" There he was, number 5891, standing right next to her.

He looked much like he had at the university. His hair slightly covered his eyes, and he was wearing a red button-up shirt and jeans.

"Hello, Amy," he smiled and waved. As his eyes darted around the table to Penny and Bernadette, he shifted his weight back and forth and crossed his arms uncomfortably.

"I don't want to interrupt," he continued. "My colleagues and I pulled some long hours at the university this evening. So we stopped in for a late dinner. I noticed you were here and just wanted to say 'Hi'… I thought it would be the polite thing to do."

"Why were you working late?" She asked.

"We are working an upcoming lesson we will be giving to middle school students explaining why Chemistry is essentially the basis of all other scientific fields."

Amy smirked to herself. She didn't necessarily agree with him, and she knew for a fact that Sheldon wouldn't either. However, the study rules prohibited her from socializing with him outside of the workplace, so she couldn't get into an in-depth argument about the matter.

She really didn't know what more to say, so she just looked up at him awkwardly.

"I'll let you get back to your dinner," Ben said, then turned and walked back to his table without saying another word. The two other men he was with stared at Amy as Ben returned to his seat.

"Ooo…" Bernadette said. "Who was that? He's a cutie pie!"

"He's someone I work with," Amy said, playing with her salad. "He actually reminds me a lot of Sheldon."

"What are you talking about?" Penny asked. "Sheldon would never have come over on his own accord and said hello to a random bunch of girls."

"We aren't random. He knows me," Amy argued. "Besides, he never said hello to you."

Penny furrowed her brow, trying to remember if that was true.

"I can't really talk about him, though," Amy said. "It's against the rules."

"Against the rules?" Bernadette's eyes widened with understanding. "Ohhh… he's in your study." Amy knew Bernadette could relate, having had been involved numerous research projects in the past.

"So, how does he remind you of Sheldon?" Penny questioned, ignoring Amy's comment about the rules.

Amy gave her an aggravated look.

"What?" Penny said. "Who are we going to tell? We're your girls! This is girls' time. Go ahead and blab."

Amy sighed. She knew Penny wouldn't leave it alone. _I may as well give in._

"They're just very similar," she said. "Neither like being touched, really. Ben's very anxious around new people, but has a genius level IQ. Sheldon's is higher, of course."

Amy paused and looked back over her shoulder at Ben. He and the two other men at his table were already engrossed in a new conversation.

"He's a little awkward, too. Although, probably not quite as much as Sheldon can be," Amy admitted. "I think Ben understands social cues a little better, and he seems a bit more willing to try new things."

"Interesting," Penny said. "I always thought Sheldon was one of a kind. I'm not sure I can handle a world where more than one of him exist."

Amy turned back to Penny. "What are you talking about? Sheldon _is_ one of a kind. I just said they were _similar_. Not the same," she snapped.

Penny held her hands out to shield herself from Amy's wrath. "Okay, _okay_… sheesh."

Amy eyes immediately became apologetic.

"Sorry bestie," she sighed. "I tend to suffer from severe mood swings just before my menses."

Penny's scrunched her nose disgust and she pushed her remaining pasta away. She and Bernadette exchanged unpleasant looks.

"Also," Amy continued, oblivious to her friends' discomfort, "It's just… Hannah accused me of being attracted to him at work earlier this week, and it upset me."

Bernadette's mouth dropped open. "That's ridiculous! Amy, I can't believe – "

"It upset me because I can't say she's completely wrong," Amy interrupted. "There was a bit of an attraction there."

Penny and Bernadette gaped at her.

"Not in any kind of romantic way!" she quickly added noticing their expressions. "I mean, Sheldon's mind is what attracted me to _him_ at first. I'd never met anyone else like him. When I met Ben I guess I was just surprised that there was someone else who intrigued me in that same way. I feel like Ben and I could really hit it off and be great friends. Just like Sheldon and I were in the beginning."

Amy used her fork to play with a cherry tomato that had fallen off her plate. "But Sheldon's the one for me. Always will be," she said.

"Believe me, I don't need to be convinced," Penny rolled her eyes.

"Yeah," Bernadette chimed in. "You and Sheldon are two peas in a pod…like a pair of homologous chromosomes … two electrons in a helium atom - "

"Thanks, guys," Amy butted in with a smile. "I just… I don't know. I feel guilty for being intrigued by another person's mind and personality. I know it's not cheating - I'd never cheat on Sheldon - but it still feels wrong."

Bernadette and Penny looked at each other, not really sure what to say. Amy and Sheldon's relationship had always confused them. For someone whose boyfriend had always claimed their relationship was 'one of the mind', they could see where Amy might feel concerned.

"Can we not talk about Ben anymore?" Amy finally said, looking up at them.

Penny shrugged. "Sure."

"I'll tell you what you _do_ need to talk about," Bernadette said.

Amy shot her a questioning look.

"Go talk to your dad about what's going on with Sheldon. It'll make you feel better to know."

* * *

**Chapter twelve coming soon!**

**Notes:** Thank you in advance for reviewing! :o)

I apologize for the delay. Reasons/Excuses include:

1) I work in news, so when there are major events (i.e., tornadoes), my life gets absorbed by work. Not that I'm complaining - I could have it worse. _*Prayers for Moore, OK and the North Texas area*_

2) The main reason this one took me a bit longer is due to some of the recent developments in the show (Raj's mutism, the D&D game, etc.). I was conflicted about whether or not to change some of the things I already had written in this and future chapters. I ultimately decided to re-write minor portions of some of my chapters which directly conflicted with these new developments, so I had to do a bit of swapping around.

Since my story is set in some ambiguous time in the show's future, it still makes sense for Leonard to be in my story (even though in the show he just took off for the North Sea), so I didn't fret as much about that aspect. I'm not really going to acknowledge that, as its not really relevant to my tale.

Just tryin' to keep it as real as possible, folks. ;o)


	12. Chapter 12: The Collaboration Friction

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 12: The Collaboration Friction**

* * *

"So, Amy," James said. "To what do I owe your visit? Not that I'm complaining, of course. It's always nice to see my girl!"

Amy smiled at him as she set her purse down beside the couch.

After more than a week of talks behind closed doors and her father's mysterious activities with her boyfriend, Amy was determined to figure out what was going on. The two most important men in her life couldn't keep the secret any longer.

She decided to just come out and say it.

"Dad… What exactly are you and Sheldon planning?"

Her dad slowly grinned. "I knew you were wise to us."

"Well, it's kind of obvious, Dad," Amy snorted. "You two are as thick as thieves."

"I haven't been purposely keeping anything from you, Amy. You haven't asked me about it and I assumed Sheldon would have told you by now. He hasn't said anything?"

"No. He refuses to," Amy threw her hands into the air. "It's driving me bananas!"

James laughed at his daughter's rather animated show of irritation and sat down next to her on the couch.

"Well, I'm not sure why he hasn't mentioned it," James started. "I honestly thought that he would have. You'll find out soon enough anyway."

Amy waited patiently for her father to continue, secretly kicking herself for not finding the time to ask him sooner. It would have spared her a lot of frustration.

"If you _must_ know, we are working on a little project together," he finally said. "It's still in the works, but - if it pans out - your boyfriend could be looking at quite a substantial amount of additional income."

Amy peered at her father. _Additional income? ... Project?_

"Oh, God," She said. "This isn't anything illegal is it?"

James laughed. "No! Nothing like that!"

James stood up and wandered into the kitchen, pulling two bottled waters out of the fridge.

"Sheldon's a very creative young man… as I'm sure you've noticed," James winked at Amy and handed her one of the waters. "He's brilliant, actually."

Amy nodded. _Of course he's brilliant. Everyone knows that._

"Our discussion when I met him at dinner really intrigued me… particularly the part about the games he developed," James shrugged. "I asked if he'd be interested in meeting with some friends of mine that I know in the gaming industry. One thing has led to another, and – long story short – They are interested in working with him."

James took a long drink of water before continuing.

"It's a great opportunity for him. I mean, obviously, his games need a bit of modification to make them marketable to the average person… but, honestly, the industry has been looking for some new ideas."

Amy was stunned. She'd always known that Sheldon was creative, and he had dedicated so much time to these personal projects of his in the past… she'd just never thought that the games that he developed could actually be sold.

Counterfactuals probably wouldn't take off anytime soon, but now that she thought about it, she could definitely see three-person chess or Research Lab being big hits in certain circles.

"Wow." Amy said. "That's great! So… why wouldn't he tell me this?"

James shrugged. "Maybe he didn't want to jinx it."

Amy knew better. "Sheldon doesn't believe in that kind of superstitious nonsense. There has to be another reason that he didn't tell me."

"I don't know, Amy," her dad said.

Suddenly, there was a familiar rapping on the door.

_* knock knock knock * _"Mr. Fowler?"

_* knock knock knock * _"Mr. Fowler?"

_* knock knock knock * _"Mr. Fowler?"

James glanced at Amy, who simply pursed her lips and stood to answer the door.

"That'll be Sheldon," She stated.

"He's a bit peculiar, isn't he?" Her father said to no one in particular, as if he had just stumbled into this realization.

Amy greeted her boyfriend before she even finished opening the door. "Hello, Sheldon."

He paled when he saw her. His eyes darted from Amy to her dad. She could tell that he was trying to come up with an excuse as to why he was there.

"Amy… I didn't realize you – "

"Don't worry, Sheldon," Amy confessed. "I already know why you're here. My dad told me."

Sheldon looked over at James.

"I thought we were keeping this a secret?" He stepped into the room.

James sighed. "You never asked me to keep it a secret. We never discussed that. I didn't know until today that you hadn't told Amy."

He noticed Sheldon's surprised expression and stood up. "I'm sorry if it upsets you that she knows now, Sheldon, but there's no reason for it to. It appears that we are going to be moving forward after all."

Sheldon stepped into the room and grinned. "Really? That's wonderful!"

"Yup," James smiled back at Sheldon. "So… if you don't mind working with me a bit longer - "

"Wait, wait, wait…" Amy interrupted. "What does this mean? What all have you done so far?"

"We have presented the basic ideas to some friends of mine at the purchasing company, and they are going to discuss it at their next meeting," her dad said. "Right now we are in the process of obtaining patents."

_This is really in-depth. They're serious._

"You've done all this in only a few days?" She asked.

"You'd be surprised what can be accomplished when you know people," James winked. "Of course, there's a lot more to do and still nothing is guaranteed at this point. But, it's definitely looking good."

Sheldon's excitement was evident in his eyes. Amy had only ever seen that expression when he was looking at his whiteboard on the verge of a big breakthrough.

Amy was suddenly hit with a wave of happiness that was too much to contain. She stepped quickly to Sheldon and stood on her toes to give him a peck on the cheek. Then she wrapped her arms fully around his chest, burying her face in his side.

"That's amazing! I'm happy for you Sheldon," her voice was muffled by his jacket.

Sheldon's breath caught in his chest as she squeezed against him. He held his arms out, unsure of what to do with them.

"Oh, you two look great together," James said with a smile.

Sheldon looked up at Amy's dad, clearly uncomfortable with this show of affection in such close proximity to him. He patted Amy lightly on the back. She felt him gently try to nudge her away with his body, so she stood back to give him some space.

James' cell phone began ringing from somewhere in his bedroom and he ran to catch it. Sheldon took the opportunity to reprimand Amy.

"Seriously, Amy… in front of your father?"

Amy blushed and smiled. "Sorry, Sheldon. I'm just really excited for you."

"Well, thank you. But, that's no reason to completely lose control of your senses."

"Wait… why didn't you share this with me before?" Amy asked with a frown.

Sheldon looked away from her.

"Ummm…" His voice trailed off.

"I thought at first that maybe my dad had asked you not to tell me, but he says never required any such thing."

"No. It's true," Sheldon admitted.

"You're horrible at secret-keeping, Sheldon," Amy pointed out. "Why would you purposely hide something if you didn't have to?"

Sheldon glanced around the room, refusing to make eye contact. "I don't know why I didn't tell you. I just… I just didn't … want… to."

"You didn't _want_ to tell me? Why not? We share everything."

"I didn't want to tell my friends yet. Not until I was sure."

"Your _friends_?"

Sheldon nodded, "I didn't want to tell you all and then have to _un_-tell it. I couldn't trust everyone not to rub it in my face if it didn't work out. It'd be like the North Pole all over again."

"I'm not your _friend_, Sheldon. I'm your _girlfriend_." Amy glared at him. "And you know you can trust me… don't you?"

Sheldon hung his head, still avoiding her gaze.

Amy took a step back from him. "Wait," she said. "Do you not _trust_ me?"

Sheldon finally looked back up at her, but was interrupted before he could speak.

"Sorry, guys! That was – " James paused as he walked in and saw the couple staring intently at each other. "Oh. Sorry… do you two need a minute?"

Amy broke her concentration on Sheldon and looked over at her dad.

"No," she said. She walked over to the couch and picked up her purse. "I've actually got to get going."

She and Sheldon may not have shared much in the way of physical intimacy, but she'd always thought that the one thing they did share was trust. They could tell each other anything.

_Obviously, Sheldon doesn't feel the same way_, she thought.

She brushed past him on her way to the door.

"Bye, Dad," Amy called without looking back. She closed the door behind her and leaned against it, fighting back a tear that was threatening to fall.

Truth be told, she loved the fact that Sheldon was getting along so well with her father, and was thrilled with the prospect of his board games catching on. She even could have handled the secrecy, if he had only been able to give her a good reason for it. But for him to just lump her in with the rest of his friends... to not acknowledge that she meant _more, _and then to essentially admit that he didn't trust her - that was too much.

She pulled her phone out of her pocket to text Penny. She needed some time with her bestie to sort her thoughts out.

_- Are you free tonig- -_

Amy's text was cut short as the door behind her popped open. She crumbled to the floor with a thud, her phone flying across the hall.

"Ow," she moaned as she rubbed her hip. She looked up and saw Sheldon standing over her.

"You could at least try to help me up," she said after a few seconds.

Sheldon leaned down and extended a hand to her, pulling her off the floor.

Once she was upright, Amy brushed her hair out of her face and glanced up at her boyfriend. She attempted to act like she wasn't the most humiliated she'd been in a long time, but it was hard to look him in the eye after the scene she'd just made in the apartment.

Sheldon pulled the door shut and stepped toward her.

"Amy…"

She finally met his gaze, red in the face… mostly because she was still fuming, but a little because of her embarrassment.

"Are you upset with me?" he asked.

Amy closed her eyes and took a deep breath. "I just need some time, Sheldon. We're okay… and I _am_ happy for you. I just need to be alone right now."

"So… you aren't upset?" Sheldon looked confused.

Amy groaned. "YES. I'm upset, Sheldon. Just… let me be alone to cool off."

Sheldon nodded.

Amy searched the floor for her phone. She found it in the corner and picked it up, clearing the half-written text message she had started.

_I'll just go home after all_, she thought.

She peeked over at Sheldon, who was still standing outside her parent's apartment studying his shoes... kicking his heel like a... _like a sexy toddler_.

_Oh, god,_ she thought_. He's so frikkin' adorable._

It took everything she had to walk past him and down the stairs without saying anything.

She made it to the lobby and froze. Just a few more steps and she would be out the door... free to go home and stew about what had happened.

But she couldn't do it. She had to know why Sheldon didn't think he could trust her with this. Maybe they hadn't advanced as far in their relationship as she thought. Maybe Amy had taken it for granted that they would continue to move forward after their private D&D game in Sheldon's bedroom long ago. But, now that she thought about it, the incident hadn't been mentioned since it happened... and aside from a bit of handholding, they hadn't made much additional progress.

She turned on her heels and darted back up the steps.

Sheldon had already left the second floor.

Amy continued the next couple flights of stairs until she reached the fourth floor. She raised her hand to knock on 4-A, but stopped herself. After thinking for a moment, she crossed the hall and knocked on 4-B instead.

Penny answered seconds later wearing oversized sweatpants and a big grin. She was obviously settled in for the night. "Oh – Hey Amy! What's up?"

"I need some advice," Amy said.

* * *

**Chapter thirteen coming soon!**

**Notes:** Reviews and constructive criticism welcome, as always! :o) I appreciate it, you guys!


	13. Chapter 13: The Kepler Comparison

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 13: The Kepler Comparison**

* * *

"What's going on?" Penny's expression changed from glee to concern upon seeing her friend's expression.

"Can I come in?" Amy looked over her shoulder at Sheldon's door. She didn't want her boyfriend to eavesdrop on them with his Vulcan hearing.

"Of course!" Penny walked over to turn off the TV as Amy entered the apartment and closed the door.

"I talked to my dad earlier," Amy began, settling into the couch. "I found out what is going on."

"Really? What are they up to? Is it bad? You look like you've been crying." Penny sat down next to Amy and placed a comforting hand on her arm.

"I can't really tell you what is going on between them," Amy said. "I don't think Sheldon wants me to… but lets just say it's definitely a good thing! And I love that they are working so closely together and are becoming such good friends. That's not what I'm worried about."

"Ok… So… then why did you want to come talk if you can't tell me?" Penny asked.

"Sheldon didn't tell me what was going on between he and my father because he says he didn't trust me," Amy said quickly. The tears were starting to build again.

"What?" Penny's face contorted in shock. "Of course he trusts you. He trusts you more than anybody I know."

"Well, that's what I thought too, but - "

"Wait. Did he actually _say_ that he didn't trust you? That doesn't sound like something he would tell you. What were his exact words?"

"Well… there were no words really. He said he didn't want to tell his friends about what was going on yet," Amy explained. "But I'm not just his friend, Penny. I'm his girlfriend. He should trust me. When I told him that, he didn't say a word. He didn't deny it."

Penny was silent.

"What?" Amy asked, wiping away a small tear.

Penny bit her bottom lip. "Sweetie, I think you might be overreacting a bit."

"Really?"

Penny nodded. "Ames, I've never seen two people more suited for each other, and I know for a fact that Sheldon trusts you."

Amy sniffed a little, but wiped the last tiny tear off her cheek. _Maybe I did overreact. I never gave him a chance to explain._

"You need to talk to him. You should go over there." Penny motioned towards the door.

Amy shook her head. "What would I say? I have to find a way to apologize for my reaction... but he still has to understand why I am upset. I need to think."

Suddenly, Sheldon's signature knock echoed through the room.

Amy looked at Penny in shock. She didn't want to talk to him now. She had to gather her thoughts first.

Penny understood Amy's pleading expression.

"Get in my room," Penny whispered. "I'll see what he wants."

Amy hustled to Penny's room and closed the door, leaving just a crack so she could hear. She peered through and saw Penny go to answer the door.

"Your ears must be burning," Penny said to Sheldon, who looked at her like she was insane.

"Why? Do I look ill?" He reached up and touched his ears, panic forming on his face. "They don't feel warm. Are they red?"

"No… Sweetie… It's just an expression."

"Oh. Ok." Sheldon paused and mulled it over. "I don't understand."

"Nevermind," Penny said. "What do you want?"

"I came to ask you something, but on my way over I thought I heard Amy's voice."

"Oh… " Penny looked around the room. "Uhhh… yeah… she's not here."

"Well, you were definitely talking to someone. It sounded like her."

Penny glanced back toward her bedroom where Amy was hiding.

"I was talking to Amy on Skype."

"Oh. I see." Sheldon looked down at the floor. "Did she tell you why she was upset, by chance?"

Penny nodded.

"Well, that's great," he heaved a sigh of relief. "Can you please tell me? Because I haven't got a clue."

Penny couldn't help but smile. "Sure. Come on in. But it'll have to be quick. I need to get to bed. I have a read-through early in the morning for the play."

Sheldon stepped in and closed the door behind him, while Penny walked over to sit on her couch. She glanced quickly to her bedroom where Amy was hidden.

"Penny?"

She looked up at him.

"Aren't you going to offer me a beverage?"

She frowned and stood up again. "Of course, Sheldon. How rude of me."

She walked over to the fridge and opened the door. "What do you want? Diet Coke?"

"Hot tea."

Penny sighed, closed the fridge, and pulled her kettle and box of green tea out of her cabinet.

"What's troubling you, sweetie?"

Sheldon sat on one of her barstools and watched as Penny filled the kettle with water and placed it on the stove.

Amy peeked through the crack in the doorway. From there she could easily see her bestie and her boyfriend.

"Amy was being very confusing tonight, Penny," Sheldon began. "She found out something about me that I haven't told anyone. At first she was pleased, but then became very angry." He shook his head and scoffed. "Women. You are all crazy."

"Yeah, Sheldon. _We're _the crazy ones," Penny smirked. "Let me ask you this… do you trust Amy?"

"Yes. Of course," Sheldon said without hesitation.

"Well, whatever it was you were hiding… why did you keep it from her?"

Sheldon thought for several moments without speaking. Amy inched closure to the door, tilting her head to listen.

"Penny, have you ever heard of Johannes Kepler's laws of planetary motion?"

"Oh, sure," Penny rolled her eyes. "We're always joking about those in the kitchens at the Cheesecake Factory."

"From your tone, I am going to assume that was sarcasm," he said.

Penny nodded and gave him a thumbs up. Sheldon seemed pleased that he got it right.

The kettle whistled and Penny went to turn off the stove.

"Ok. Well, one of Kepler's laws states that as planets orbit around the Sun, they change speeds. You see, the planets' orbits are elliptical, and the closer a planet gets to the sun, the faster it goes. Then, as its orbit extends further from the sun, it slows down again."

He paused to let it sink in.

Penny just stared at him, dumbfounded. "Ok, honey. Now _you're _sounding like the crazy one. I don't see what space has to do with anything." She placed a teabag in his mug and poured hot water over it. "What's your point?"

Amy was just as confused as Penny. _I have a PhD and don't even understand what he's trying to say,_ she thought.

Sheldon grabbed hold of the teabag and dipped it in and out of the water a few times. As Penny circled around the bar and sat down on the couch, he followed and settled in next to her.

"My point, _Penny_," Sheldon began, "Is that apparently Amy was upset that I didn't tell her what was going on - "

"Actually, It's because you didn't trust her," Penny pointed out.

"I _do_ trust her," Sheldon corrected. "But, there are points in my relationship with her when it begins to move so very quickly… I become _overwhelmed_."

Penny set her own mug down on the coffee table. "What do you mean?"

"It's like the laws of planetary motion, Penny," Sheldon said with an air of annoyance, as if she should have grasped his point by now. "If you think of my relationship with Amy like one of the planet's orbits, I am the Sun and Amy is - say - Mercury."

He looked at Penny, who continued to watch him with a raised eyebrow. Sheldon heaved another frustrated sigh. She clearly wasn't getting it.

"Let me dumb this down for you. I'll come at it from another direction," he said. "Surely you've heard of the conservation of angular momentum?"

Penny looked away and nonchalantly cleared her throat, not wanting to admit that she had no idea what he was talking about. But, Sheldon picked up on her ignorance and shook his head before continuing. "It's like an ice skater spinning. With her arms out, she spins slower. As she brings her arms in, the skater speeds up."

"Oh!" Penny exclaimed as if a light bulb had just been turned on somewhere in her brain. "I _have_ seen that! But, I still don't see how it relates to you and Amy."

"The closer we get to each other," he explained, "the faster the relationship starts to move. At first, I try to accept the change like the skater pulling in her arms, or the Sun's gravity tugging on the nearby planet. But, as we get closer, things move faster. I end up wanting to slow down and take a breath. I push Amy away, just like the Sun releasing Mercury from its pull... or the skater extending her arms again."

Penny didn't say anything. She just listened, trying to make sense of it all.

"Once Amy is at a manageable distance and things slow down, I can take everything in," Sheldon said. "I can breathe again. Then something new comes around and things speed back up."

Sheldon looked into his mug of steaming tea.

"First of all," Penny said, straightening up in her seat. "I'm giving myself brownie points for understanding about 65% of that."

Sheldon rolled his eyes.

"Sheldon, sweetie," Penny said with determination, "You have to understand that, from others' perspectives, you and Amy are moving about as swiftly as a pair of snails. I don't see that you are going very fast at all."

Sheldon groaned. "I _know_ how our social group views my relationship with Amy. That was made abundantly clear to me after you all imposed on our D&D game the last time we played together."

Penny hung her head.

Amy knew that her friend felt guilty that the group had forced her into a publicly awkward situation with Sheldon. She still hadn't told Penny exactly what had happened behind closed doors in his room, even though Penny had asked several times. _Some things should just be kept between a woman and her man_, Amy had reasoned with herself.

_That's probably one of the things Sheldon is talking about, though_, Amy thought. He welcomed -even suggested- their private D&D adventure, but who knows what he thought after she left that night. _Maybe he panicked? Maybe he wasn't as ready for that as he let on?_

"You all _think_ you understand us," Sheldon continued, scowling at Penny. "But you all are just like specks on one of the planets in my metaphor. From your perspective, you can't feel it's motion. You don't even know the planet is moving. There's no way you can understand what Amy and I have or how fast it is going from your vantage point."

Amy wiped away another tear, but this time it wasn't from sadness or confusion. Sitting on the floor in Penny's bedroom, she absorbed her boyfriend's words. She was leaning back against the wall, clutching her knees as she listened to him explain their unique relationship to her best friend.

Not just explaining it… _defending_ it.

Amy was beginning to understand. Things _had_ been moving quickly for them lately. First, it was handholding. Then, he had to meet her parents... only to became their neighbor a short time later. Not to mention, this special project he was working on with her father.

Sheldon was just trying to maintain some distance... some independence. It made complete sense now. He had always relied on and thought mostly about himself, and now he had a whole other person's life that he was trying to incorporate into his own. And that was the key - _he was trying_.

_I have to talk to him. _She stood and began to open the door, but caught Penny's eyes. Her friend shook her head and motioned for her to stay in the bedroom.

Amy backed up and closed the door again.

Penny quickly looked back at Sheldon as soon as he glanced her way.

"Sweetie," Penny said, as if nothing had distracted her, "You need to talk to Amy about this. But give her the night to cool off. I'm sure she will understand. She was just hurt tonight. That's all. You need to explain how you feel."

Sheldon looked annoyed. "_That's_ your advice? '_Talk to her_'?"

"You're the one who asked for my opinion," Penny said with a huff. "I don't know why... you never like what I tell you. And I only understand half of what you say anyway."

"Well, _of course_ I need to talk to her. That's a given," he argued. "It's like you're not even trying." She narrowed her eyes in irritation, but the gesture was lost on him. "You know more about relationships, having been in _so_ many," he said, earning another glare from Penny. "I thought you might have some sort of brilliant insight."

He shook his head and handed his mug to her. Penny looked down at it and frowned.

"You didn't drink it," she said.

"You didn't make it right." He stood and walked to the door. "Thanks anyway, Penny."

"Anytime." Penny smiled at him as he left. After all these years, she was used to the way her quirky friend operated.

Once Sheldon was gone, Amy opened the door to Penny's room.

The two stared at each other.

"Ames... He doesn't just trust you... he _really_ cares about you. He just needs some reassurance that his world won't implode as you two move forward. And _you_ need to be the one to reassure him. I can't do that for either of you."

Amy nodded. Penny was right.

"Don't talk to him now, though," Penny said. "You need to spend tonight thinking of something to say in response to that ridiculous physics lecture he just gave me."

Amy snickered, but agreed. Sheldon needed to relax... and she had to think of a way to help him do that.

* * *

**Chapter fourteen coming soon!**

**Notes:** Please review! Constructive criticism also appreciated! ;o)


	14. Chapter 14: The Vintage Reversion

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 14: The Vintage Reversion**

* * *

The next day after work Amy went straight to Sheldon's apartment to try and clear things up between the two of them, but he wasn't at home.

It was Friday, which meant it was vintage video game night. She expected he would be there any minute, lest his routine fall into disarray, so she decided to wait outside his door for him to return.

She settled onto the top step of the staircase outside his apartment and pulled her phone out of her pocket to call her mom. She hadn't had a chance to talk to her since she'd gone back to Philadelphia.

Her mother answered quickly. "Hi, Amy!"

"Hey Mom!"

"How have you been, dear?"

"Oh, I've been doing okay," Amy said. "It was a busy week at work, but it's the weekend now! How are things in Philadelphia? Are you all packed?"

Her mom sighed heavily. "Well, yes. Everything is all packed up, and is already on its way to Pasadena. But, I am having more trouble than I thought that I would putting the house on the market. It seems there is a lot more that needs to be done before it can be listed."

"Oh," Amy said. "What does that mean? What kind of stuff?"

"Oh, just basic things - some repainting, some small repairs. Our realtor wants me to take care of it before she shows it or has any open houses."

"That sounds like a lot of work!" Amy said.

"Yes, well, I think I can handle it. It just means that I can't come back to California right away like I was hoping."

"Well, I'll be sure to keep an eye on dad for you," she laughed.

Her mom snickered back. "Yes. Please do. I should be there hopefully in the next two weeks or so. How are things with you and Sheldon? Are he and your father getting along?"

Amy detected a slight tone of hope in her mother's voice. Not hope that James and Sheldon were being friendly… more like hope that they _weren't_. Even though she had always pushed her daughter into a relationship, Amy had been surprised that her mom was clearly not happy with her choice in Sheldon. Amy wasn't quite sure why. To her mom's credit, though, she tried her best to not let it show. Unfortunately, she wasn't always successful.

Amy played with a piece of lint on her sweater. "Yes. They are getting along quite well, actually," she said with just a hint of defiance. "And Sheldon and I are … really good."

"I know your father was excited to meet him. It was one of the things he was looking forward to most with the transfer."

"Well, they are definitely bonding," Amy said. Just then, she heard the familiar sound of Sheldon and Leonard coming up the stairs.

"Oh! I have to go, Mom. Sheldon's actually arriving home right now. I need to speak with him."

"Sure," Carol said. "I'll talk to you later, hon. Love you."

"Love you too." Amy hung up the phone and dropped it in her pocket.

She stood up just as Sheldon and Leonard rounded the corner. They were discussing which version of 'The Legend of Zelda' was the best, but stopped when they saw her.

"Amy?" Leonard said.

"Hi Leonard… Hi Sheldon."

Sheldon's eyes darted to the floor.

"Have you been waiting long?" Leonard asked. He and Sheldon finished walking up the stairs, as Leonard pulled his keys out to unlock the door.

"No. Not long," she replied. She took a moment to study Sheldon. He was purposely avoiding her eyes. "It's vintage video game night, right?"

"Yes," Leonard grinned. "We just picked up a copy of the original Legend of Zelda! It should be amazing. I haven't played that one in years!"

They all entered the apartment and Leonard plopped the bag with the game down on the coffee table. "Do you want to play?" he asked.

"Oh. No, thank you," she said. "Video games don't interest me. I actually came to discuss something with Sheldon." She looked over at her boyfriend. He was still staring at his shoes. He hadn't said a word since he saw her. "If it won't disrupt your evening too much, that is."

"Of course," Leonard said, glancing at his roommate. He was finally picking up on the tension. "Uh… I can leave you two alone."

Leonard started to walk back to his room, but Sheldon stopped him.

"That won't be necessary," he said. "Howard and Raj will be here any minute with the food. Amy and I can talk in my room."

To Amy's surprise, Sheldon grabbed her hand and led her past Leonard and down the hall.

Once in his room, Sheldon shut the door and looked at Amy.

They spent a moment silently processing one another, then both spoke at the same time.

_"I talked to Penny."  
"I talked to Penny."_

They blinked at each other.

Amy nodded, "I know you did."

"Oh." He cleared his throat and clasped his hands behind his back. "Well, it seems I owe you an apology." He said it almost in a whisper, as if it was painful to admit.

Amy shook her head. "No, Sheldon. I'm the one who owes _you_ an apology. I never gave you an opportunity to explain yourself last night."

She sat down on his bed and patted the space next to her. Sheldon took the seat.

"I know you trust me," Amy said. "I overreacted."

Sheldon scoffed. "That's the truth."

She couldn't stop a half-smile from forming.

"I still feel hurt that you didn't think you could tell me, your _girlfriend_," she said. "But, I understand that I have probably been asking a lot of you lately… relationship-wise, I mean."

Sheldon took her in, studying her expression as if trying to work out a puzzle.

"Amy, despite what some people may say or think," he said. "I _enjoy_ being in a romantic relationship with you. True, I don't necessarily approve of all aspects of the _traditional_ romantic relationship... which you have _clearly_ allowed yourself to be swayed into pursuing, by what I can only assume to be peer pressure... but ours is unique. And you keep me on my toes. I like a challenge. That's why I devoted my life to string theory."

Amy didn't know how to respond. She hadn't realized that he had been picking up so strongly on her increasing interest in further intimacy. Even though she hadn't necessarily been hiding her feelings, she had always assumed him to be blissfully unaware of the extent of her desires. Apparently, he had just been choosing to ignore it.

"But I'm limited by more than just my overall lack of understanding about the relevance of romance, Amy." Sheldon continued. He reached over and plucked her hand off the bed, then placed their clasped hands in his lap. "Just doing _this_ makes me… uneasy, for lack of a better word." he said. "It's unusual for me. It's uncomfortable. My skin tingles. It feels… unnatural."

_I know the feeling_, Amy thought. Her whole arm was tingling from his contact. She could feel her cheeks begin to flush from the closeness and intimacy of the moment.

He looked down at her hand and studied it.

"It's not an outright _bad_ thing, but too much of it at once and I can't think. It's overwhelming."

He placed her hand gently back onto her own lap and let go. Amy looked at the appendage as if it was no longer a part of her body… as though it had been completely removed and replaced with an alien hand.

"I need you to understand where I am coming from, Amy," Sheldon twisted his body to face her. "The reason I didn't tell you about what I was working on with your father… "

"You don't have to explain that," Amy said. "I get it. I do. You needed some distance."

Sheldon looked elated. "Thank you! I was hoping you'd understand, but was worried that your unpredictable female hormones might have obscured your ability to see reason. I'm happy to see you are above such nonsense."

"Well, lets not get hasty, Sheldon." Amy said quickly. "I am still a lady, after all. As you _seem_ to be aware, I do fall victim to some hormone-based urges and additional 'nonsense', as you call it." Sheldon frowned at her used of air quotes. "However, you're right. That doesn't mean I can't see the bigger picture… which is why you have nothing to apologize for."

"Thank you, Amy." Sheldon said. "And if you are still concerned about whether or not I trust you… I do. If I didn't trust you, I wouldn't try to push myself like this."

Amy knew that, of course. She smiled at him. The stress of the past few days was written on his face. _He needs a break_.

"Sheldon, why don't you go enjoy your video game? Have a night away from me. Don't even think about us – "

"That's impossible," he interrupted.

"No… go ahead. I won't mind. Enjoy your time with the guys."

"It's not being away from you that is the problem, Amy," Sheldon argued. "We just played Halo the other night and you weren't there."

_That's true,_ she thought.

"Well, then what is it?" Amy frowned. "I don't know how else to give you space."

"I never said I _wanted_ to be away from you. Physical distance isn't the issue. It's just…" His voice trailed off.

Amy leaned in with a raised eyebrow. "It's just... what, Sheldon?"

"I want to not think about you _all_ the time," he said quickly. "I can't get anything done. _What would Amy think about this? Amy would like to hear this story…"_ Amy smiled as he mocked his own thought process. "It's ridiculous that my life is so absorbed by your opinion. It shouldn't be that way. My mind has important things to focus on. The future of particle physics may be at stake. Not to mention, it's killing my Halo technique."

Amy snickered, and Sheldon shot her a glare.

"Sorry," Amy said. "Well, I don't know what to tell you, Sheldon."

"You're the neuroscientist," he said. "Isn't this your field of study? What good is a PhD if you can't put it to use?"

"How about this, Sheldon?" Amy began. "How about if we don't push each other for a while. I'll give you time to adjust to my parents being around. I'll let you work with my father and won't butt in. We will just carry on like we did in the past… before things got so overwhelming."

"Like a reboot?" Sheldon asked.

"No. Not like a reboot. We won't be undoing anything," Amy said. "We'll consider it an experiment. It will be fun. Like a look back in time."

Sheldon tilted his head in confusion. "I'm not sure I understand. Unless you possess a TARDIS, wormhole or time-turner, I don't see how we can possibly see into the past. Besides, I have no need. I have an eidetic memory."

Amy frowned at him. "I'm not being literal, Sheldon. I just mean that we will spend some time doing the things we used to do when we first started our relationship… when it wasn't so confusing. We can assess the results of the experiment at our next date night. Which is… "

"In thirteen days," Sheldon finished her sentence.

"Right. So, we won't discuss our relationship for almost two weeks. No expectation of any romantic displays, either."

"Wait… we won't break up will we? If the experiment goes poorly, I mean." Sheldon was suddenly very worried.

"I don't see how it could go poorly... but, no. We won't be breaking up. I just don't want you to have to worry about me all the time. You shouldn't have to constantly be concerned with how I will react or what I will think of something you do. I want you to be comfortable."

"Okay…" Sheldon didn't seem convinced.

"Look," Amy said, noting his concern. "I want you to think of me as someone you can laugh with. Someone you can share things with. Not as a source of frustration or someone you have to please all the time."

"But I thought you said that I should treat you differently than my friends," Sheldon pointed out. "Now it sounds as though you want to be treated like a friend? You women make absolutely no sense."

_He has a point,_ Amy thought. _I did say that. Women really are confusing._

"Listen, we're still in a relationship, Sheldon. But, this will be like vintage video game night," Amy added. "Why do you play vintage games?"

"Because its fun to go back to the original every now and then," Sheldon said. "It also helps you to appreciate the newer versions of the games, because it allows you to see all the progress that has been made in graphics and game play."

"Exactly," Amy said. "I want us to take a view weeks to go back to the vintage version of our relationship."

"Vintage Sheldon and Amy," he said. "Interesting."

"This doesn't mean that we will stop progressing," Amy clarified. "It just means that we are taking a few weeks to breathe. To appreciate each other. Then on date night we can discuss the results of our little experiment... and compare it to how our relationship is now. We can even make a chart if you'd like to look see a visual representation of the data."

Sheldon's eyes lit up. He liked analyzing data... especially when charts and graphs were involved.

"The Relationship Agreement still stands during this time, though," he said forcefully.

"Of course," Amy said. "You're still my boyfriend after all. Don't go shacking up with another woman." She winked at him.

Sheldon gave her his classic look of haughty derision.

* * *

**Chapter fifteen coming soon!**

**Notes:** Please review! ;o) Constructive criticism is also very much appreciated.

I'm going to try and squeeze at least one more chapter in before I go on vacation for a couple of weeks (won't have internet access). I'll do my best to get the next one posted, but then will have a brief hiatus. The next chapter just has some minor tweaking that needs to be done, so I think I should be able to manage it. *fingers crossed*


	15. Chapter 15: The Testing Variation

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 15: The Testing Variation**

* * *

By the end of the weekend, Amy's dad had received all of the items that her mom had sent over from Philadelphia. With Leonard, Howard, Raj and – occasionally – Sheldon's help, James had managed to get most of the items unpacked and into the apartment. The rest had to be put in a nearby storage building until her parents were able to find a house.

Meanwhile, Amy and Sheldon had been enjoying the "vintage" version of their relationship. On Saturday, while Sheldon waited for his laundry to dry, they played a rousing game of counterfactuals, and on Sunday, the couple spent the afternoon in Sheldon's apartment. Amy read the latest issue of _Neuron_, while Sheldon worked on some equation on his white board. Most of the day was spent in silence, simply enjoying each other's company. The topic of their relationship was never breeched, nor was the board game project he was working on with James.

By Monday, Amy felt a lot better about Sheldon. He seemed to have relaxed already, which meant she could focus on her work without worrying about him passing out from stress.

"How was your weekend?" Hannah asked as Amy walked into the lab. She noticed Hannah was wearing wide-rimmed purple glasses today.

Amy grabbed her clipboard and joined her coworker at the table.

"It was great, actually! How about you?"

Hannah shrugged. "Fine. Nothing to write home about. I'm ready to get started with work, though."

Amy sensed something was up, but she was also eager to get started, so she let it go.

"Now we are getting into the really good part!" Amy said. "This is what we've been waiting for!"

Hannah smiled at Amy's excitement.

This was the day all their preparations would begin to pay off. They would be officially starting their study. The subjects would be brought in and shown different pictures and video clips to see how their brain activity changed when subjected to various stimuli.

"Well, let's call them in!" Hannah said. "Who's up first?"

Amy went to the lobby and brought in a young woman with curly blonde hair named Abigail.

"Hello again, Abby," Amy said as she led her to the table.

As Hannah hooked Abby up to the equipment, the door to the lab opened and Amy heard the click of high heels approaching their lab table.

Amy turned to get a look at their visitor - a tall, thin woman with short brown hair and glasses. It was the head of the neurobiology department, Dr. Laura Coleman.

"Dr. Coleman!" Amy said with surprise. "We didn't expect you to come by."

The woman smiled and nodded. "No, I like to occasionally pop in unannounced. It helps give me an idea of how everyone is doing on an every day basis."

Hannah stood up and shook Dr. Coleman's hand.

"If you don't mind," Dr. Coleman added. "I would like to observe for a bit."

"Of course," Hannah said, pulling up an extra stool.

Dr. Coleman sat down and leaned against the table. "Don't mind me," she said. "Carry on."

Amy and Hannah both nodded, and finished prepping Abby for the study.

"So, Abby," Hannah said. "As you know, when you applied you were asked to send in some pictures of people and places from your personal life. We have mixed those in with slides of random photos from other places and events."

Abby nodded.

"All we will be doing is gauging how your brain activity changes in response to the different photos."

"Okay," Abby's voice was high-pitched and sweet.

Dr. Coleman crossed her arms and leaned back as the test began.

While Amy took notes, Hannah flashed through the photos.

_A picture of Mt. Rushmore._

_An image of the Los Angeles skyline._

_A woman, most likely Abby's mom._

_A picture of the Mona Lisa._

_A picture of a boy, probably Abby's boyfriend or brother._

Amy scribbled on her notepad as Abby's brain patterns changed when the familiar pictures came into view.

When the photo segment was complete, they moved on to the video portion of their study. The clips that played were scenes from different movies. One was an action scene with fighting and a lot of gore, the next was a romantic love scene, another was a sporting event.

After about an hour of tests, everything was done. Amy walked Abby back into the lobby and brought in their next subject, an elderly man named Roger.

They replicated the process with several more people, as Dr. Coleman silently watched their every move.

Their last subject of the day was Ben.

He followed Hannah over to the table, counting his steps along the way.

Once he was seated, Amy began to explain the process to him. Ben confirmed that he understood with a small nod. When Hannah began attaching the electrodes to him, he looked just as uneasy as he had on the first day.

"It was good seeing you the other night," Ben said to Amy in an attempt to distract himself. "How was your dinner?"

Amy glanced at Dr. Coleman uncomfortably. She and Ben were not supposed to be associating with each other outside of the lab.

"It was good, thank you," Amy said.

She turned to Dr. Coleman, who was eyeing her suspiciously. "I bumped in to Ben here while I was at dinner with my friends the other night," Amy explained. "He was kind enough to stop and say hello."

Dr. Coleman nodded and looked back at Ben, who was scrunching with discomfort while Hannah finished up.

"Ok, Ben," Hannah said once everything was in place. "Let's get started."

They began to flash through the images again.

_Mt. Rushmore._

_Los Angeles._

_A picture of a woman with blonde hair and a big smile._

Ben's brain activity spiked upon seeing this picture. Amy made a note of it, and Hannah pressed the button for the next slide.

Amy wasn't sure who that woman in the photo was, but she must have been important to Ben. _Maybe a sister?_

After all the slides and the video clips had been completed, Amy disconnected Ben from the monitor.

"That took longer than I thought," Ben said.

Amy laughed. "Yeah, just over an hour. I suppose it is a long time to sit still."

"You're telling me," he said.

Ben was already starting to fidget as Amy finished removing the electrodes. As soon as she was done, he stood up. "Are we finished for today?"

Hannah nodded. "Yes. We'll give you a call when we need you back in."

Ben nodded and followed Amy to the door.

"Well, I guess I might see you around," he said. "Seems like we frequent the same places. I'd love to have a scientific discussion with you sometime."

Amy glanced back at Dr. Coleman and Hannah. Luckily, neither had heard his comment.

"Yeah, we aren't really supposed to be seeing each other outside of the lab," Amy whispered.

"I know," Ben nodded. "But it's rude not to say 'hi' if you see someone you know. At least, that's what I've been told."

Amy smiled. "You're absolutely right. See you later, Ben."

As Amy returned to the lab table, Dr. Coleman excused herself from the room, commending the two on their work for the day.

After she left, Hannah grinned at Amy.

"What?" Amy asked.

"So, you two had dinner, eh?"

Amy rolled her eyes. _Not this again._

"I thought we discussed this last time," she said. "And we didn't_ have dinner._ We were just at the same restaurant and he said hi. Good grief."

Hannah snickered. "I know, I just like getting you all agitated."

Amy smirked at Hannah.

"How's the wedding planning going?" Amy asked, trying to change the subject.

"Oh… yeah. About that…" The smile faded quickly from Hannah's face. "That may be put on hold."

Amy frowned. "What do you mean? Is something wrong?"

Hannah stood up and started packing up her paperwork.

"Um… well… remember I told you Mark's family doesn't care much for me?"

Amy nodded.

"Well, I think they have been trying to talk him out of the wedding. He hasn't said anything yet, but I can sense something might be coming down the line."

"Oh..." Amy wasn't sure what to say. "Do you mind me asking why they don't like you? You seem perfectly pleasant. I don't see how anyone could dislike someone with such a delightful personality."

Hannah sighed and sat down again.

"You don't have to tell me," Amy said quickly. "I just –"

"I cheated on him." Hannah hung her head. Her eyes studied the floor.

"Oh." Amy said.

"I never said I blamed his family for not liking me," she pointed out. "Mark knows about the affair, of course. It was a long time ago and was a one-time thing. He understands that, too… which is why he didn't cut me loose when it happened."

Amy sat down next to Hannah and wrapped her arm around her.

"I'm sorry." It was all Amy could think to say without more information, but she didn't want to pry any more than she already had. Amy certainly didn't condone cheating, but she didn't like seeing her friend upset either.

"It's okay," Hannah said, finally looking up at Amy. "If he calls it off, then he calls it off. Its what I deserve for what I did, right?"

Amy bit her lip. "I don't know, Hannah. It seems like something you need to discuss with Mark. You said he knows the affair was a one-time thing… so maybe if you talk it out, everything will be okay."

Hannah gave Amy a weak smile. "We'll see."

She started packing up her papers again. "Thanks for listening, Amy. I didn't mean to make you uncomfortable."

Amy shook her head. "No, not at all. You can always talk to me."

Amy couldn't imagine what she would do if Sheldon ever cheated on her. Of course, she knew that would never happen. Yet another reason Sheldon was the best boyfriend in the universe. She could trust him completely, just as he could trust her.

* * *

Later that evening, Amy was beginning to regret her decision to Skype with Sheldon. She had been listening to her boyfriend gripe about Leonard's recent violation of the roommate agreement for about half an hour.

Apparently, Leonard had deleted one of Sheldon's recordings of a lecture on string interaction and attachment to D-branes.

"This is now the second time he's done this, Amy," Sheldon complained. "Something has to be done. I hate to say it, but I think I might have to give him his third strike... which means I'll have to have him take the class again."

He sighed. "I don't think people realize how much of a burden this puts on _me_. I have to prepare the curriculum all over again. It will really cut into my schedule."

"You could just _not_ give him the strike," Amy said. "Or waive the class requirement."

Sheldon gasped. It was as though she had just claimed loop quantum gravity held more merit for the unification of gravity with quantum mechanics than did string theory.

"_Not give the class_?" Sheldon said, aghast. "What kind of precedent would that set? Before you know it, nothing would be taken seriously. There would be chaos and rioting."

"I doubt there will be rioting, Sheldon," Amy said with an eye roll.

He ignored her and pulled out his phone to look at his calendar.

"I suppose I could give the class this Thursday…" he said. "But I was going to ask you if you wanted to go out to eat that day. I guess I could reschedule that…"

"Wait," Amy interrupted. "What do you mean you were going to ask me out to eat? Our date night isn't until the following Thursday."

"It wouldn't be a date," Sheldon said. "No boyfriend/girlfriend activities, remember? I'm going to eat with James that day, and thought you might want to join us and spend some time with your father."

"You're eating with my dad?"

"Well, yes, Amy," he said. "We are working together. It stands to reason that we would be meeting on occasion to discuss our progress. But, I'll have to reschedule that if I need to hold a class for Leonard."

"I think Leonard's had the class plenty of times," Amy said. She was anxious to go out to eat with Sheldon and her dad again. "Can't you give him a pass on this one? Or maybe let him do it online?"

"An online class?" Sheldon pondered the suggestion. "That is intriguing. That certainly would make it easier on me…"

"Yes. It would! I think you should put together an online course for him to take."

"Alright, I think I will," Sheldon said with a smile. "You know, Amy, I never would have thought about that. I knew there was a reason I kept you around. Thank you!"

Amy nodded. "You're welcome. So… dinner? Thursday?"

"Oh, yes." Sheldon said. "Would you like to join your father and I?"

"Yes, of course!" Amy said.

"Then it's settled." Sheldon keyed the information into his phone.

"So, you don't mind me tagging along for a business discussion?" Amy asked. She had promised him that she would not pry into his dealings with her father.

Sheldon waved his hand in the air as if he was brushing her comment away. "We won't be discussing much business, honestly. Just a couple of things. It will be more of a social dinner."

"A social dinner?" _How perplexing._ "Do you regularly meet with my dad for social visits?"

"On occasion." Sheldon was still engrossed in his phone, and didn't bother looking up at Amy to respond.

_Interesting_. He typically wasn't a fan of socializing of any sort. Even when he was out with the guys, he often make it known that he was only there because he deemed it a social 'obligation'. Amy wasn't sure if he thought of these visits with her father the same way.

_Oh well,_ Amy thought. _No sense looking a gift horse in the mouth._

She was simply excited to go out to eat with her boyfriend. Maintaining a "vintage" relationship was proving harder than she thought it would be. Since they had promised each other that they would not try to make any kind of romantic advancement towards one another - something she knew Sheldon would have no problem achieving - she had been trying to force all romantic thoughts about her boyfriend out of her head. She'd assumed it would make the days until their next date night easier to manage.

However, the reality was that it was having the opposite effect. She found the "forbidden" aspect of it quite exciting. She was quick to jump at any opportunity to spend more time with him... even if she was the metaphorical 'third wheel' at a dinner with her father.

She couldn't wait.

* * *

**Chapter sixteen coming soon!**

**Notes:** Please review! Constructive criticism appreciated, too!

This will be my last chapter for a couple of weeks, as I am going on vacation and will not have internet access. However, the upcoming few chapters are mostly written (just a few changes needed here and there), so I should be able to post again not long after my return! :o)

Don't abandon me during the hiatus, please! _*bats eyelashes*_


	16. Chapter 16: The Dyad Magnetism

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 16: The Dyad Magnetism**

* * *

Thursday couldn't come soon enough. Amy was finding it more difficult that she thought it would be to maintain the "vintage" version of her relationship with Sheldon. She hadn't realized how much progress they had made until they began conducting this little experiment.

She found that she missed spending time with him on a romantic level. To the outsider, of course, it had never appeared as though they were being romantic… but it was the little things: the occasional light touch that sent tingles down her spine, the meaningful glances that had so much fire behind them, and the knowledge that at any point in time she could reach out and grab Sheldon's hand or give him a peck on the cheek - fully expecting to be reprimanded, of course - but it was exhilarating nonetheless.

She had found the past several days extremely trying, to say the least.

Meanwhile, she could tell Sheldon was eating it up. He loved their in-depth discussions about various scientific articles in recent publications, and their debates over the latest advancements in string theory testing. Talking with Sheldon was easy. Their mental connection had always been strong.

In fact, Amy was growing increasingly concerned that her experiment may backfire.

She had hoped that Sheldon would see that the progress they had made over the past few years hadn't really changed who they were as scientists, thereby giving him more confidence to move forward on a romantic level. However, Amy couldn't help but notice that her boyfriend seemed more and more at ease with the "vintage" notion. She was growing worried that Sheldon would become complacent.

Truthfully, they _had_ changed. Not as scientists, but as a couple. Their experiment had enlightened Amy to exactly how much. True to her word, though, she had been sure not to make her feelings known. Not until next Thursday.

_This_ Thursday, though, she was going to be going out to dinner with her boyfriend for the first time since the night he met her parents. She dared to let her mind drift to the romance that the evening might lead to.

_No, Amy._ She told herself. _Don't think like that. _Besides, any potential romance would be a bit stifled by the fact that her dad would be present. She couldn't complain too much, though. Sheldon was, after all, making an effort to bond with her father. And from the looks of things, her father enjoyed his company as well. She couldn't have asked for a better situation.

She and Sheldon arrived at The Cheesecake Factory and were seated before James arrived.

Penny was off this evening. The rehearsals for Cat on a Hot Tin Roof had really kicked into gear. She spent every other weeknight at the theater practicing and running lines with the cast. Of course, as this disrupted Sheldon's routine, he was none too pleased. However, with time - and some nudging from Leonard - Sheldon had managed to learn to trust the other waitresses at the restaurant to bring his order out correctly.

"So, Amy," Sheldon began. "Where would you like to go for our date night next week?"

"Oh… I thought we weren't discussing anything to do with our relationship until then?"

"Well, we have to plan, Amy. We aren't just going to 'wing it'. Good Lord." Sheldon rolled his eyes and Amy giggled.

"Well, I'll let you pick. Why don't you organize our evening?"

Sheldon thought about it for a moment then nodded. "Very well."

Their conversation ended as Amy noticed her father come through the door. She waved him over to the table, and as soon as he was seated the waitress came by to take their order.

Sheldon's ordering process wasn't nearly as ridiculous as the first time that they had all gone out to eat together, because this time Sheldon knew exactly what he wanted. His usual.

"Sir, I don't know what your 'usual' is," The waitress said.

Sheldon sighed. "Barbecue bacon burger and a lemonade."

She jotted it down on her pad, took Amy and James' order, then shuffled back to the kitchen.

"How has work been, dad?" Amy asked. "And how's mom? When is she going to be able to come back to California?"

James took a drink of water and smiled at his daughter. "Work's been great! Couldn't ask for a better team. Speaking of work…" He pulled out a small stack of papers and handed them to Sheldon. "Here, Sheldon. I need you to fill these out and get them back to me. Take time to read them over, of course. There's no rush. Just some minor paperwork that they are requiring from you."

Sheldon took the documents from him and began to peruse them as James returned his attention to Amy.

"You're mother's fine. She finally got the housework completed and we are getting it listed soon. She told me that she will be back probably by this time next week... fingers crossed."

"That's good," Amy looked over at Sheldon, who had finished a cursory review of the paperwork and had stuffed it away into his messenger bag.

"I enjoyed our game the other night, Sheldon," James said. "It only instilled more confidence that we are on the right track here." He winked at him.

"Thank you, I enjoyed it too." Sheldon grinned.

Amy was just as confused as could be. "What are you talking about? What game?"

"We played a round of Research Lab," Sheldon explained. Then he couldn't hold back a snicker. "Of course… your dad then _insisted_ we attempt three person chess with only the two of us."

James laughed too. "Yeah, that was a mistake."

"I told you it would be," Sheldon said smugly.

James noticed Amy's curious expression. "We ended up taking turns being the third player," he explained. "But nothing ever got accomplished because we kept trying to use the third player to take each other out. It was just a constant back and forth. It was pretty funny."

Amy's eyebrows were still raised.

"I guess you had to be there," James said with a light laugh, then took another drink of his water.

"So…" James continued. "I want to hear about you two."

Amy and Sheldon glanced at each other. She knew they were both thinking the same thing. They had promised each other _they_ would not to discuss their relationship, but hadn't considered that her dad might bring it up.

Amy cleared her throat. "Um… what do you mean?"

"Well… how long have you been dating? You seem very comfortable with each other."

"We've been dating a few years," Amy said. She didn't want to get into specifics, in hope that her dad would drop it. She was trying to come up with a way to transition to another topic… maybe her work? _But how_?

Sheldon was drinking his water, in an attempt to avoid adding anything to the conversation.

"Have you two been talking marriage at all?" James pressed.

Sheldon coughed into his water, and Amy patted him on the back.

James just laughed at him. "Sorry. I know that's an awkward subject, especially with your girlfriend's father."

The waitress returned with their meals and frowned at the water that had spilled around Sheldon.

"I'll be right back with a towel," she said. She left the tray of food on a stand and disappeared back into the kitchen.

"Dad, that's kind of a personal thing. Sheldon and I haven't discussed that yet." She glanced at Sheldon, who was nervously wiping water off his pant legs with his napkin. Amy wasn't sure if he was more concerned by the conversation or the spilled water.

James nodded and held up his hands. "Fair enough. Forget I said anything. I just really like you two together. I think you are heading in the right direction. That's a good man you've got there, Button. Hard worker."

Amy smiled at her dad, but Sheldon fidgeted uncomfortably in his seat, staring at his burger on the tray next to the table. Amy knew he was anxious to have his food in front of him, so he could focus on something else.

"Well… I'm not sure mom would agree with you," Amy muttered under her breath.

Sheldon didn't need his Vulcan hearing to pick up on what Amy said. It wasn't even said quietly enough to escape notice by her dad, who had regular, human hearing.

"Oh, you just have to give your mom some time," James said. "She'll come around. You have to admit, she and Sheldon didn't exactly get off to the best start."

"I don't understand," Amy argued, now completely ignoring the agreement she had made with Sheldon not to discuss their relationship. "Mom has been pushing me for years to get a boyfriend. And she meets Sheldon – and she starts to hit the brake."

Sheldon, who had been listening to Amy and James' conversation in confusion, finally spoke up.

"Wait," he said. "Does your mother not like me?"

_Shoot_. She had forgotten that Sheldon had never picked up on her mother's lack of excitement about their dating, and Amy had obviously chosen not to speak about it with him.

"Of course she likes you, Sheldon," James said, coming to Amy's rescue. "She's just having a hard time letting her daughter go. She wants to make sure she's in good hands." He turned back to Amy. "Your mom hasn't had the time to get to know Sheldon like I have."

Sheldon looked over at Amy. She could tell he was thinking hard about something. She wasn't sure what, but she could tell he was hurt.

The waitress returned with the towel and wiped up the water, then quickly placed their food in front of them and left to help another table.

"Oh, great. Who knows how many tables she wiped down with that old rag before rubbing it all over the spot where she put my plate." Sheldon frowned in disgust. "The table is probably teaming with millions of microbes now. And my food is sitting right on top of it all."

Distracted by the possible plague growing underneath his plate of food, Sheldon seemed to have forgotten about the conversation they had just been having. Neither Amy nor James wanted to bring it up again, so Amy grabbed at the opportunity to change the subject.

"So… My work's been going well," Amy said. There was no easy transition. She just had to make the jump and hope the awkwardness cleared out of the air on its own.

"That's good to hear," James said as he took a bite of pasta. "Are you making any breakthrough discoveries?"

Amy smiled. "No. It's too early. And I really doubt that any of our work will be breakthrough, honestly. Similar tests have been done in the past."

"Well, I'm sure you will have fantastic results regardless," he said.

The rest of their dinner continued with relatively little additional tension. Sheldon remained quiet for most of it, occasionally peering over at Amy, studying her.

James had arrived at the restaurant in a cab straight from work, so after their meal Amy offered to drive both Sheldon and her father home.

She walked the two of them up the stairs, and gave her father a hug goodbye on the second floor.

Sheldon extended his arm to James for a farewell handshake; something Leonard had explained to him was a 'non-optional business obligation'. James grabbed his hand, but pulled Sheldon into a loose hug – much to Sheldon's shock and dismay. The horror was written on his face, but, luckily, James missed it.

"We're practically family," James said. "We can give each other hugs."

Sheldon just looked at the floor without responding, but James didn't think anything of it. He turned and disappeared into his apartment.

Amy and Sheldon stood there for a moment in silence. Sheldon shifted uncomfortably, and Amy still sensed that he was thinking hard about something.

_He's probably calculating all the ways that tonight skewed the results of our experiment._ Amy sighed, then finally decided to break the silence.

"I guess I'll be going."

Sheldon nodded.

Neither of them moved.

Amy didn't know what else to say, so she started to pass him and walk down the steps. As her shoulder brushed his, Sheldon grabbed it.

"Amy, wait."

She turned and looked up at him.

His blue eyes searched hers… as if he was trying to work out what he wanted to say.

"Yes?" She asked.

His hand slid from her shoulder down to her elbow, and he stepped forward slightly… his mouth hung slightly open as his brain still tried to form the words.

"I...um…"

She wasn't sure if it was pent up sexual frustration, the fact that he looked particularly titillating this evening, or just that she wanted to comfort her boyfriend – he had, after all, just found out that her mom was less than thrilled by their pairing. Whatever it was hit Amy like a wave. She suddenly had a strong desire to kiss him. It was more intense than it had ever been in the past. And, for the first time in her life, as she looked into her boyfriend's eyes, she sensed that the feeling _might_ be mutual. But, she couldn't be sure.

_I'm probably crazy_, she thought to herself. Sheldon finally had several days without her making romantic advancements and thinly veiled comments about their relationship... why would he try something now? _It doesn't make sense. It's... illogical._

Besides, they had agreed. No relationship stuff until next Thursday. This would ruin the experiment and Sheldon wouldn't be happy with that. Tonight's events had already made enough of an impact on the results._ Yes, that's it,_ she thought._ He's just worried about the experiment.  
_

Still, as he stood lightly touching her elbow, the air felt like static electricity. She thought for sure her hair was standing straight out on end.

"I…" It was unusual for him to be so speechless.

_Surely I can't be the only one feeling this?_ Amy thought to herself. _This can't just be me._ She tentatively inched toward him.

Then she saw it in his eyes… the reality of the situation was hitting him. He backed up a step and removed his hand from her arm.

"I will let you know what our plan is for Thursday," he said quickly, repositioning his messenger bag over his shoulder.

"Oh… ok. Sure." Amy said, disheartened. "Is that all?"

He nodded, looking at the floor.

"Ok," Amy reluctantly turned and walked down the steps, away from what was no doubt the most romantically charged moment she'd ever had in her life... and nothing had even happened.

_Next week is going to be ridiculously hard,_ she thought.

* * *

**Chapter seventeen coming soon!**

**Notes:** I'm back from vacation – mostly unscathed (save for a very awkward looking sunburn). Ha! Please review/critque! As always, thank you for your support!


	17. Chapter 17: The Relationship Homogeneity

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 17: The Relationship Homogeneity**

* * *

Amy shuffled through her charts and data that she had taken over the past two weeks for her little experiment with Sheldon.

It was the night before date night, and she wanted to make sure she had everything prepared when she presented it to him.

She hadn't been able to concentrate in her apartment; there were too many distractions. The laundry needed to be done, and her computer was sitting right there… the Skype button luring her to click on it and chat with her boyfriend. So, she had moved down the street to a small deli, where she was sipping on a cup of hot tea as she scribbled through some of her sentences and made notes in the margins.

She had just finished highlighting one of her statements about how she felt the night after their dinner with her father, when a shadow fell over her paperwork.

She looked up and saw a familiar face.

"Hello," Ben said.

Amy quickly turned over the papers so he couldn't see what she was working on.

"Hi, Ben," she replied. "Do you live around here or something?" She sure seemed to run into him quite often.

"No… but I do come to this deli a lot. They have good soup."

Amy wasn't sure what to say, so she nodded and said nothing.

"May I sit down?" he asked. He looked around the restaurant. "There's nobody else we know here from your university, so I don't think we'll get in trouble."

Amy glanced around too, as if she was searching for someone to tell her what to do.

_Oh, this is ridiculous. There's nothing wrong with talking._

"Sure," Amy finally said. She pulled her purse out of the seat across from her and hooked it over the back of her own chair. She stacked all her paperwork up and stuffed it inside her bag.

Ben sat down in the now empty chair and unfolded a napkin in his lap.

"I've already ordered my food, but I'm sure I can get the waiter's attention…" Amy looked behind her for signs of the man who had taken her order.

"That's not necessary," Ben said. "I'll just ask for a drink when he comes back. I've already ordered some soup and a sandwich to-go."

Amy nodded and leaned back in her chair, then began fingering her napkin. She suddenly felt very awkward. _This may not have been a good idea, after all._

She looked up and noticed Ben studying her.

_I hope he hasn't fallen in love with me. Darn these curvy hips!_

"Amy…" Ben said, as he straightened the silverware on the table. "I feel like we would get along well… outside of the lab, I mean."

_Crap. He's fallen in love with me. _Though, she couldn't argue that they would get along well. She felt that connection too. She'd always thought they would make great friends.

"Why?" Amy asked.

"You don't look at me like I'm insane, for one thing," he shrugged. "Most people think I'm nuts."

Amy smiled._ Makes sense. Ben is quirky. Most people don't 'get' quirky._

"You remind me of my boyfriend," she said. "People always tell him he's crazy, too. And he doesn't like touching… at all. Just like you."

Ben scrunched his eyebrows. "Really? I've only ever met one person even remotely similar to me…"

His voice trailed off, and he looked up at Amy as though he wanted to say more.

Amy shifted in her seat uncomfortably. Surely he wasn't coming on to her? She had just mentioned she had a boyfriend._ Maybe I should casually reiterate that fact?_ There was a moment of silence before Amy spoke again.

"I feel that way with Sheldon. My whole life nobody ever understood me." She looked down at her hands. "Until I met him, that is. The moment we met, I knew I had found a lifelong friend. And now, we're something more."

Ben gave an understanding nod. "Sounds like Claire."

_Wait… what?_

Amy looked up. "Who?"

"CLAIRE," Ben said loudly.

"No… I heard you the first time," Amy said. "I meant… who's Claire?"

The waiter came over and placed the sandwich Amy had ordered in front of her.

"I'm sorry, sir," the man turned to Ben. "I didn't realize there would be two at this table. Did you want to order something?"

"Just an iced tea, please."

The waiter nodded and walked away.

Ben shifted in his seat and watched Amy as she lifted the top piece of bread and sprinkled pepper over her sandwich. She felt slightly foolish. For a moment, she considered apologizing to Ben for misreading his motives, but decided against it. He hadn't heard what she was thinking, after all.

"So?" Amy nudged. "Claire?"

"Claire is my… I'm not sure what she is."

"Girlfriend?" Amy asked.

"No. I don't think so."

_He doesn't think so? What does that mean?_

Ben noticed Amy's confused expression. He set his elbows on the table and leaned in, speaking softly.

"You say I remind you of your boyfriend… Sheldon, was it?"

Amy nodded.

"How do you two… I mean… How did you … work it out?"

Amy's eyebrows scrunched even further. "Work it out? What do you mean?"

Ben leaned back in his chair again and re-straightened the silverware that he had accidentally bumped out of place.

"Um…" He began. "How did you two work out the… physical… part of your relationship? Since you say he dislikes touching."

"Oh!" Amy's eyes grew as big as golf balls.

Ben was uncomfortable, Amy could tell. She was uncomfortable too. But she was also intrigued. Was there another couple out there like she and Sheldon?

"Um… well…" Amy wasn't exactly sure how to explain the physical part of her relationship. She wasn't even sure she understood it herself.

The waiter returned with Ben's iced tea.

"Anything else?" he asked as he set the glass down in front of the chemist.

Ben and Amy both shook their heads. They avoided eye contact with the waiter, embarrassed, as though he had been eavesdropping on their entire conversation.

Once the waiter was out of earshot, Amy and Ben looked at each other again.

"Ben, I'm not sure I can help you there," Amy whispered. "Sheldon and I… we…"

"You don't have problems in that area, huh?"

Amy couldn't hold back a laugh, which she immediately regretted. She could tell Ben had taken it the wrong way, and she didn't want him to think she was making fun of him.

"No! I mean… Yes! We definitely have… issues… in the physical department."

Amy put her hand on Ben's, and he impulsively pulled it away and leaned back.

"Sorry," she said. Amy scanned Ben. He looked disappointed. She wasn't exactly sure what he had been expecting her to say, but she felt like she needed to help him out.

"Ben, do you know what I was working on before you came up to my table?" Amy asked.

"How could I possibly know that?" he scoffed.

_Just like Sheldon,_ she thought, mentally rolling her eyes.

"I was working on charts to explain my relationship."

"Is that something you are doing for work? Some kind of weird brain thing you neuroscientists are into?" Ben looked somewhat disgusted by the idea.

Amy shook her head. "No. It's something I am doing for me. And Sheldon. For us."

"I don't understand," he said.

"Ben, you and Claire… are you 'together'? Does she want to be… physical… with you?"

Ben shrugged. "We aren't dating, if that's what you mean… or maybe we are. I don't know. She wants to, though. I can tell. I'm pretty smart, if you haven't noticed... and kind of a catch."

Amy ignored Ben's arrogance and thought back to her charts. They are just where she and Sheldon were a couple of years ago, before they became 'official'. _I'm Claire_, she thought. Then, she remembered Ben's reaction to the photographs in the lab.

"Ben, is this the woman whose photo was in our slides at the lab? The one with blonde hair?"

Ben nodded.

Amy smiled. When Ben saw that picture during the study, it triggered the same reaction in his brain that most people get with something they really enjoy. It was the same sensory response associated with happiness, and love.

Amy turned around and pulled the charts she had been working on out of her bag. She looked through them and handed one to Ben.

"Look," she said.

Ben took the paper and glanced it over.

"What am I looking at?" he asked.

"This is where Sheldon and I are right now, when it comes to a physical relationship," Amy pointed at a spot on the chart. "As you can see here, we've only just now begun regularly holding hands. I sneak a few kisses in here and there, but he is never too pleased when I do that."

Ben brought the chart closer to his face and studied it.

"This is… more than three years?"

"Yes."

Ben looked relieved. He handed the chart back to Amy.

"Amy, I've known Claire for a year now… but I'm not sure she is as understanding as you appear to be with Sheldon. I'm not there yet, but I can tell she wants more."

"Have you asked her out?"

"We go places all the time," he nodded.

"No. I mean, have you asked her to be your girlfriend?"

Ben shook his head. "Why would I do that?"

"Ben… I thought you wanted advice about your relationship? Obviously, if you are asking me about it, then there is a must be a relationship you are hoping to begin? Or one you hope to save?"

Ben frowned. "We are great friends. We enjoy each other's company. But she does try to 'get closer' every now and then. That's why I am talking to you about this. How do I get her to stop?"

Amy grimaced. It was all she could do to get her own boyfriend to move faster. She wasn't going to help perpetuate someone else's non-physical relationship. She didn't want Claire to be in for many more years of what she had been through. Not if she could help it.

"Ben," Amy said with a scowl, "If you want my help, its not going to be advice on how to slow your relationship down. It's going to be how you can cope with increasing affection… and I can explain ways you can move forward at a pace you can be comfortable with. I won't help you backslide. That's what I'm trying to prevent with Sheldon. Do you want to lose Claire?"

Ben crossed his arms and muttered something under his breath.

"What was that?" Amy said, leaning in.

He looked up at her. "Fine. How can I move forward without… freaking out?"

"Good," Amy smiled. "First things first… You need to ask that girl to be your girlfriend before someone else snatches her up."

Ben looked horrified. "That seems like a really big step. Isn't there something else… like… I don't know… buying her something?"

Amy shook her head. "If you want to maintain your relationship with her, you are going to have to progress in a pattern marked by a few big leaps, with several smaller steps intermittently in between. And I think you need to start with a big leap. Get past the first hurdle."

Ben eyed Amy and muttered something quiet and unintelligible.

Amy crossed her arms and leaned back in her chair. She was enjoying this. Not only was she helping Ben – and poor Claire, someone she had never met, but both admired and respected already – but she was also learning a bit more about how someone with a mind like Sheldon worked.

If Claire's image sparked that kind of response in Ben's brain, she pondered what was going on in Sheldon's brain when he looked at _her_.

As she was lost in thought, her eyes drifted to the entrance of the deli and she gasped.

Dr. Coleman stood in the doorway.

Amy considered ducking under the table, but it was too late. Her boss had seen them both, and was staring curiously at Amy.

* * *

**Chapter eighteen coming soon!**

**Notes:** Thanks for reading! As always, reviews and constructive criticism are much appreciated! :o)


	18. Chapter 18: The Experiment Analysis

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 18: The Experiment Analysis**

* * *

This was, without question, the worst day of Amy's life.

She wiped away the tears as she drove home from work.

After catching her with Ben at the deli the night before, Dr. Coleman had put in for Amy's immediate removal from her study at work. She hadn't even given her a chance to explain.

Ben was removed from the study group as well, in order to ensure the results were not tainted by any outside influence.

In all the commotion, Amy hadn't even thought about tonight's date with Sheldon. She had all her charts and graphs done, but couldn't imagine being happy again for the rest of the day.

_Maybe I should call it off?_ She thought._ We could reschedule for another day._

But she couldn't do that to Sheldon. Not at the last minute. He had everything planned already, and he hated having to change his schedule so abruptly.

No, she would have to go. Maybe after getting cleaned up she would feel better.

As soon as she got home, she hopped into the shower. She just stood under steaming water, letting it pour over her face. It washed away her tears, but it couldn't wash away her thoughts about what had happened. She couldn't shut her mind off. What would she do now? Thankfully, she still had her job, albeit no longer as part of a study.

She turned off the water and grabbed a towel.

She was both infuriated by _and_ thankful for her conversation with Ben. While it was Ben who had asked to sit with her, she couldn't blame him for what had happened. She was ultimately responsible for her own actions. Still, she was angry.

But she was also overjoyed.

She and Sheldon were not alone in their… _peculiarness_, and that made her happy.

Amy was beginning to feel better. She dried her hair and got dressed, admiring her new cardigan and skirt in the mirror. She smoothed out the pale purple fabric over her hips and turned sideways, assessing herself.

Date night always managed to put her in a frazzle. She wanted to look nice and wear something that Sheldon wasn't used to seeing her in; but because of his eidetic memory, this usually meant she had to buy new clothes for the occasion. She brushed out her hair and pinned it back.

_I do look nice tonight_, she thought. She had to put on a little powdered makeup to hide the fact that she had been crying. She typically didn't wear makeup, so it felt a little strange.

Amy glanced at the clock. 5:45. Sheldon wouldn't be expecting her for another forty-five minutes. She decided to use this time to take one last look at the charts and data she had completed the night before.

She had taken the experiment very seriously, and was sure Sheldon had done the same. Amy had made a note of everything they had done together over the past two weeks, and compared it to the current status of their relationship. Ultimately, she had determined that the experiment was a success. It showed their progression quite well.

Her first chart depicted how the amount of physical contact between the two of them had increased over the years, and a corresponding chart showed the level of discomfort or happiness each point of contact seemed to produce. She used a basic 1-10 scale for that information, but would of course need more input from Sheldon to complete the data.

She also had put together a written report describing her personal emotional responses over the previous two weeks. Like any good scientist, she left nothing out. Of course, this meant she would be opening up her feelings to Sheldon in a way she never had done… but it was all a part of the process.

She reminded herself of what she told Ben the night before: _Several small steps marked by a few big leaps_. This was definitely going to be one of their leaps.

Once she had everything in order, she slung her bag across her chest and left.

The quiet drive to Sheldon's apartment allowed Amy's thoughts to drift back to the events of the day. She hadn't even had time to speak to Hannah about what happened. _I hope someone explained to her why I didn't show up? Surely they did._ _Oh my gosh! What will Hannah think? _Undoubtedly, the tale of she and Ben had been morphed into something sinister or tawdry by the time it got to Hannah's ears. _Like a bad game of telephone at all those slumber parties I never got invited to, _she thought. Amy made a mental note to call Hannah later._  
_

By the time she arrived at 2311 Los Robles, she was in tears again. She got to 4A just before 6:30, their scheduled meeting time, and took a minute to compose herself outside the door before knocking.

Sheldon greeted her as soon as her hand finished rapping against the door.

"Hello, Amy," he said with an unusually genuine grin.

Amy smiled weakly back at him. "Hi Sheldon."

Sheldon frowned. "What's wrong?"

_How could he tell? He never picks up on emotions._

"Nothing. I'm fine, Sheldon." She squeezed by him and walked into the apartment, but froze when she saw what he had done.

There were candles lit on the coffee table. The light bounced around the dim room and onto plates of Chinese food nearby.

She turned back to her boyfriend, her mouth hanging open in shock. "What's this?"

Sheldon shrugged and closed the door. "It's dinner, obviously."

"Yes, but..." Amy turned back to the table. "Why the candles?"

"Leonard and Koothrapali told me that candles were romantic. Is this not correct?"

"It's perfect!" Amy dropped her bag on the floor and put her face in her hands. Tears had begun to fall again.

Sheldon looked confused.

"I don't understand why you are crying. Is it the scent of the candles? I asked the lady at the store which scent would be best. She insisted on some horrible aroma made up of lavender and jasmine. It was quite literally an assault on my olfactory receptors. I went with pine instead, because reminds me of East Texas. Maybe that should have been a sign? _Oh, who am I kidding?_ _Of course it is a sign_. Why would I want anything that reminds me of East Texas? I should have listened to her and gone with one of the more sickeningly floral odors..."

Amy wiped her eyes. The makeup had come off on her hands. She frowned at the mess and went to get a paper towel.

"The smell is great, Sheldon." She tore the towel from the roll and rubbed the makeup off her hand.

He grabbed her bag off the floor and set it in his desk chair, then followed her over to the kitchen.

"Then… what's wrong?"

Amy dried her face off and looked at him.

"I've had a rough day. That's all," Amy said. "But you're making it better. Thank you."

"You're welcome." She could tell Sheldon wasn't sure what exactly he had done to make her day so great, but he eagerly accepted the complement. "I'll never get a handle on human emotions, I guess," he added under his breath.

Amy laughed and threw away her paper towel.

"Do you want to eat?" He asked. "The food's getting cold."

Amy nodded. She straightened her cardigan and walked over to her spot on the couch. Sheldon joined her in his own spot and handed her a plate.

"Is Leonard out with Penny tonight?" she asked, taking a bite of her orange chicken.

Sheldon nodded. "Yes. He said something about watching a rehearsal for her play. Sounds awful."

"Well, I don't know, Sheldon. Penny's quite good."

"Yes, but a rehearsal? Why watch something that isn't hasn't been polished? The audience is only meant to see the finished product… not the messy preparations."

Amy took a drink of her water and set down her glass. _He has a point._

"How was your work today, Amy?"

_Oh crap. Here come the waterworks again._

Amy set her plate on the table and turned her face away from Sheldon. She bit her lip, trying to stop the tears before he could see.

"Amy?" He set his plate down and touched her shoulder.

"I got kicked off the project!" Sheldon jolted at her outburst and Amy erupted into tears once more.

"What? Why?" He looked nervously around the couch for something he could give Amy that might quell her tears. He found a napkin and held it out for her.

"Does it matter?" She didn't really want to get into a discussion with Sheldon about Ben. That conversation would take more time to explain than she wanted to spend on it. She grabbed the napkin from him and blew her nose.

"Well, of course it matters!" Sheldon said, scrunching his nose at the soiled napkin in her hands. "If you were wrongfully removed, you can fight back and possibly get reinstated."

Amy shook her head and sniffled. "No. I broke the rules."

"Do you want to talk about it? Please, don't feel obligated."

Amy smiled at him through her tears. "No. Thank you, I'd rather not discuss the details."

"Ok." His shoulders relaxed in obvious relief.

"I'm just concerned that with this being my second removal from a project, I might not get assigned to another study for some time."

Amy had been removed from her nicotine addiction study not long ago. It certainly didn't look good for her professional resume to have two incomplete studies on her record in such a short span of time.

Amy sniffled again and buried her face in her hands.

"Amy… do you…" Sheldon gulped, obviously dealing with some deep, internal struggle. "Do you want a hug?"

Her head popped up in shock. "What?"

"Do you want a hug?" he repeated with a bit more confidence. "You offered me a consoling hug in my time of need. I would like to extend you the same courtesy."

"Um… that would be nice," she looked at her feet, and twisted the napkin in her hands. "Thank you."

Sheldon inched closer, unsure of exactly how to begin. Amy quickly put the soiled napkin on the coffee table, and brought her hands back to her lap, preparing herself for her boyfriend's embrace. He reached his arms out awkwardly and wrapped them around her, pulling her close to him.

Amy's tears stopped immediately at his touch. She breathed heavily and her heart rate sped up.

Sheldon rested his head on top of hers and patted her shoulder. "There, there."

Amy grinned and hugged him back as she closed her eyes and relaxed into his chest. _It's so nice and warm. _Her breathing slowly returned to normal, and after a few moments, Sheldon released her and scooted back into his spot.

"Better?"

She nodded. "Thank you."

"Well," Sheldon said, looking at their plates with disappointment. "Our food is now officially cold."

"That's ok," she laughed. "I wasn't all that hungry anyway."

Sheldon pushed his plate away and stood up. He wandered to his desk and pulled out a bound set of documents, then returned to the couch.

"Well, shall we 'get down to business', as it were?" he asked.

Amy had almost completely recomposed herself, and found that she was eager to get started.

"Yes. Let me get my data." She went to her bag and pulled out her own paperwork.

"Here," she said. They exchanged results and she sat back down in her spot. She hoped that he would think the experiment was as much of a success as she did.

"I think this experiment was an absolute failure," he said without even looking at her charts.

"Huh?" ... _A failure? Why?_

"Amy, the past two weeks were awful… and it proved nothing."

Amy felt a little hurt. Yes, the experiment was hard, but she had thought it was wonderful overall. By going back to their roots, it had shown exactly how much they had progressed over the years.

She looked down at his paperwork with a frown, but then something caught her eye.

One of his charts was titled 'Satisfaction Comparison'. Sheldon had marked down his relative feeling of happiness based on various points in their relationship.

"What's this?" she asked.

Sheldon looked up from the paperwork Amy had given him and glanced at his own chart in her hand.

"Well, that one seems pretty straightforward, Amy. Its all right there." He pointed at the document, indicating it was self-explanatory.

According to his chart, Sheldon had been increasingly 'content' - his word - until the point that the experiment began. At the beginning of the "vintage relationship" the numbers began to decline, with a sharp drop the night that they had gone out to eat with her father.

"But…" Amy peered closer at the data. "Wouldn't this prove that the experiment was a success?"

Sheldon gaped at her. "Success? What are you saying? I hated the whole thing. It was like the Great Depression, sans the unempoyment and bread lines."

Well, this was news to Amy. She thought for sure that he had been loving the freedom of the past few weeks.

"But, Sheldon, even data perceived as bad can still be helpful."

"Explain." Sheldon said.

Amy frowned. For a scientist, he didn't seem very intuitive on these matters. _I guess there's a reason he's a theoretical physicist, rather than experimental._ She'd heard about his failed experiment in the arctic, after all; though, she had sworn to Penny that she would never mention it to him.

"Any change in data is _some_ sort of result," she explained. "You were happy until we started our experiment. Why might that be?"

Sheldon shrugged. "I don't know. I just assumed that the decline was a byproduct of all the extra work I had to do keeping track of this data."

_Typical. He's seeing what he wants to see._

"Ok… well, look at your chart here." Amy pulled out another one of Sheldon's data sheets titled 'Breakdown of Time Spent with Amy'.

His eidetic memory had allowed him to go back through the years and make notes of the significant times they had spent together, including the exact dates of the encounters and a description of what had occurred.

She held that paper up next to his happiness chart.

"See? The points where you are happiest were around the same time that we made some significant move forward as a couple." She looked over at him. His eyes darted back and forth between the charts. _Had he really not already made this comparison?_

"Sheldon… how could you not have you not noticed this?"

He continued to stare at his charts and shrugged. "I was merely keeping track of the data. I hadn't studied it or made any hypothesis yet."

Amy set his paperwork down on the couch next to her and snatched one of her own charts out of his lap.

"_Hey - !_" Sheldon tried to grab the paper back, but Amy held it out of his reach.

"Here, look at this." She picked up Sheldon's 'happiness' chart again and held it up next to the similar one of her own.

"They're identical," He said with a hint of curiosity. "Except for that little blip there." He pointed to the night they had gone out to eat with her father. His happiness had plummeted, whereas hers had almost topped the charts.

"Well, lets discuss that, shall we?" She set the charts down. "Why weren't you happy that night?"

Sheldon stiffened next to her. "Are we _really_ going to have an in-depth discussion about _feelings_, Amy? I thought we were just going to go over each other's information?"

Amy frowned at him. "Yes, Sheldon. That's the whole point of tonight. We're supposed to be analyzing our data. And that requires some discussion of feelings, yes."

Sheldon narrowed his eyes at her, and they glared at each other in silence, both refusing to budge. After a moment he groaned and threw up his arms in frustration. "FINE."

Amy gave him a victorious smirk, and Sheldon just frowned at her.

"If you _must_ know... I was unhappy for a number of reasons," he said. "Discussing marriage with your father was uncomfortable, for one. Then, I found out that - for some crazy reason - your mother disapproves of me. And _then_, I - " He stopped short.

Amy leaned in and waited a moment, but he didn't continue. He just looked down at his hands folded in his lap.

"You what, Sheldon?"

He finally looked up at her. "I wanted to prove to you that your father was right."

_What?_

"What do you mean?"

"James. He said that I was a good man. He defended me at dinner. He said that your mother wants to make sure that you are in good hands with me."

"And that's bad because…?" Amy asked with a raised eyebrow. "I'm sorry, Sheldon. I'm not following."

"Well, while _he_ seems to understand how amazing I am, for some reason I felt like I not only needed to prove it to your mother... but also to you. But I couldn't do it."

_Couldn't do what? _Amy was lost.

Sheldon could tell she was puzzled, and he gave her a 'give-me-a-break' look. "I know you wanted me to kiss you that night."

Amy blushed and straightened her skirt before tucking her hands snuggly beneath her thighs.

"Don't deny it," Sheldon said arrogantly, crossing his arms. "I may not be good at reading people, but I'm getting better about reading _you_."

Amy didn't know what to say. She just stared at the charts in shock. Her mind racing.

_So he had, in fact, been planning on kissing me!_ This made her heart swell. _But why would he think he needed to prove himself to me? He knows I worship his every move... doesn't he?_

There were several moments of silence before a look of awareness spread across Sheldon's face.

"Hey, wait a minute! Why am _I_ the only one having to spill my guts here? What about _you_? Why does your line spike so high on that day? Its almost the exact opposite of mine."

Amy blinked quickly, trying to gather her thoughts.

"Umm…" She had reviewed all this last night, but suddenly words were failing her. The reality that she would be sharing her feelings with Sheldon hit her like a Mack truck. _This is what I've been wanting. Why is this so difficult?_

"Now, Amy," Sheldon said in a patronizing tone. "We agreed. Tit for tat."

She looked up at him and took a deep breath.

"Well... I guess the reasons I was so happy were the same reasons that you were so uncomfortable," Amy began. "I mean, I don't necessarily want to discuss marriage yet either, but its nice to think about the future. Admittedly, all that business about my mother wasn't so great… but when you and I were in the hallway, I forgot all about that."

Amy looked up at him to gauge his reaction to her confession so far, but he was unreadable.

She gulped before continuing. "I… uh… I just felt so close to you, you know? I… um… I thought you were going to kiss me. And you're right… I wanted you to. I was disappointed when you didn't. But, ultimately, the night left me… _giddy_… for lack of a better word. It just really made me think about the future and its possibilities."

She took another deep breath and glanced tentatively over at Sheldon.

He nodded. "Ok."

_Ok? That's it?_

"Sooo…?" Amy said.

"So, what?"

Good question. _So what? _What had she been expecting to happen?

"Ummm... So... what do you think, I guess? After a cursory look through all of our data, what's your preliminary conclusion for the experiment?"

He sat up straight and gazed off into the distance, deep in thought. After a moment, he looked at her again.

"I guess the only logical conclusion here is that we keep making progress as a couple. I'll have to work on the things that make me uncomfortable, and _you_... you have to work on your mother. And your patience."

Amy couldn't contain her excitement. She bounced up and down in her seat like a toddler, but Sheldon frowned at her.

"I said we'd move forward. I didn't propose, for crying out loud."

"I know, Sheldon. I just… This whole time I was so worried that you would like going back to how we used to be so much that you would just want to stay that way."

"Amy, I already said I was miserable the past couple of weeks. And earlier this month, you practically forced me to admit that I like the way you challenge me. We didn't need this whole ridiculous experiment to prove that."

"It's just nice to have it supported by tangible, scientific evidence."

Sheldon nodded. "Yes. I suppose I see where you would find comfort in that. And it did make me realize that neither of us have suffered as scientists as a result of our pair-bond, so... that's comforting, too." He rose from his spot and began to gather his things. "Now, if we're done with all this nonsense, it's time for our date to begin."

Amy looked up at him with surprise. "Date?"

"Well, yes, the term 'date night' indicates that at some point there will be a 'date'."

"But, I thought…" Amy began, looking around in confusion.

"You thought what?"

"I thought that _this_ was our date." Amy said, motioning to the charts and the meal and candles.

"This? Of course not. This was just the relationship analysis portion of our evening. I'm sure as heck not going to listen to another month of your nagging about me not being romantic. So, I have quite the night planned, if I do say so myself."

Amy's heart skipped a beat.

"You do?"

"I don't see why you are so surprised. When I noticed that they were would be giving a lecture on Planck scale dynamics and black holes, I knew it was something we had to attend. Nothing more enrapturing, in my opinion."

Amy sighed. "You do realize that I'm not a physicist, Sheldon?"

"You don't need to be a physicist to appreciate the delicate workings of our universe." Sheldon smiled. "That's what makes physics great."

He looked off into the distance and heaved a blissful sigh, then looked back down to Amy and extended his hand to her. "Shall we?"

Amy placed her hand in his and he pulled her up from the couch. As long as he kept looking at her with those eyes, he could take her anywhere.

* * *

**Chapter nineteen coming soon!**

**Notes:** I can't express enough gratitude for all the reviews so far! Thank you for your continued support! :o)

Sorry for the delay in posting this chapter. It was quite a bit longer than my average chapter (about twice as long, actually!), so it took more time to do my editing.


	19. Chapter 19: The Scientific Convergence

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 19: The Scientific Convergence**

* * *

Sheldon and Amy arrived at the lecture hall early, so that he could find the optimum seat for what promised to be a packed room.

Amy swooned as her boyfriend led her through the ornate lobby and into the auditorium – his had still clasped in hers. They're hands had barely parted since they'd left Sheldon's apartment.

Once in the lecture hall, Sheldon dropped her hand and scanned the rows. He left Amy standing at the back of the large auditorium while he moved from chair to chair, finally settling on one that he claimed was unobstructed by the podium, and wouldn't require him to move every time another person had to get up to go to the restroom.

"If everyone would plan their bodily functions accordingly, then nobody would have to worry about that sort of interruption."

Amy followed him over to the seat he had chosen and set her purse down in the adjacent chair.

"Well, I suppose I should go ahead and find the ladies room then," Amy said with an eye roll. "I wouldn't want to bother you during the presentation."

Sheldon gave her a thumbs-up and Amy left in search of the facilities.

_You'd think they would be right next to the auditorium,_ Amy thought, as she scoured the hallways. More and more people were beginning to filter into the building, and it was becoming harder to navigate through the lobby area.

Finally, Amy found the line for the restroom, which, unfortunately, already had attracted quite the crowd. She found a spot in line outside the ladies room door and leaned against the wall to wait her turn.

She still couldn't believe the progress that had been made that evening between Sheldon and herself. They had been holding hands all night! Amy relished in the fact that if anyone had seen them walking into the building, they would immediately know that she and Sheldon were a couple.

"_Amy?!" _A familiar voice pulled her out of her reverie.

Amy looked up and searched the crowded hallway for its source. Her eyes finally fell on a blonde bombshell pushing her way through the throngs of people.

"Penny?!"

Her bestie squeezed past a pair of rather rotund gentlemen and practically fell into Amy's arms.

"What are you doing here?" Amy asked.

"I blame Leonard," Penny said, adjusting her shawl and strapless dress, which had twisted slightly when she pushed through the crowd. "My rehearsal ended about an hour ago, and he noticed that this lecture was on the university's calendar." She rolled her eyes. "He pretty much dragged me here kicking and screaming."

Penny positioned herself in line behind Amy, much to the chagrin of the busty, affluent-looking woman behind her.

"Oh, put your big girl panties on and deal with it," Penny told the stranger.

Amy smiled. She couldn't believe she was best friends with such a bully. _This must be what it was like to be a part of the 'cool' crowd in school._

She suddenly realized that it had been quite some time since she had last spoken to her best friend. Amy had missed the girl talk. She hadn't noticed just how much until this moment.

"How was your rehearsal?"

"Good! We ran through it two times tonight." Penny had an accomplished glow about her. "I've already got everyone's tickets for opening night. You are still planning to come, right?"

"Of course! My parents, too."

Penny smiled.

"Is the understudy still giving you trouble?" Amy asked, as the line shifted down a few feet.

"I've still got my eye on her," Penny said. "But ever since I told her about the time I shot a soup can from 52 yards away with my dad's Beretta, she's kind of backed off."

Penny winked at her. "Anywho - what are you doing here, Ames? Since when do you follow neutron-particle whatcha-call-its?"

"The presentation is on Planck scale particles and black holes, actually," Amy explained. "And this is part of Sheldon and I's date night."

"Oh… I see. Well, do you mind if we sit with you? I don't want to interrupt your date." Penny asked.

"I'd love to sit next to you!" Amy probably came across a little too eager. _My boyfriend on one arm, and my best friend on another? Who could say no to that?_

Penny pulled her cell phone out of her small clutch as the line moved up again. The girls made it through the door and into the bathroom. "I'll text Leonard and let him know to be on the lookout for Sheldon."

After the girls left the restroom, they set out in search of their men.

Penny followed Amy back to the place she had left Sheldon. Leonard had already found him, and had saved a seat for Penny next to Amy's chair. Raj had also joined the group and was seated on the other side of Leonard.

As the audience members filed in, people pushed against one another trying to squeeze into seats.

Sheldon looked like he was in hell.

"Everyone needs to just sit down already!" He cried out to nobody in particular. "This is worse than herding cattle! The presentation's about to begin!"

"Hi, Amy," Leonard smiled as they walked up. Raj waved at them, too.

Amy and Penny took their seats next to their respective boyfriends. Sheldon's face was red with anger from all the activity. Amy patted her hand on his as she sat down.

"Relax," she said.

He looked down at her hand on his, then up to her eyes. The redness slowly faded from his face and he grasped her hand in the chair.

Amy smiled to herself, but didn't want to make a bigger deal out of it than it was. They had promised to move forward. The more she freaked out about small steps like holding hands, the more Sheldon would freak out, too. _This is the new normal_, she told herself.

But Penny caught her eye, and Amy could tell her blushing gave her away. Her friend motioned to their hands with her eyes then wiggled her eyebrows up and down. Amy couldn't hold back a goofy schoolgirl grin.

"It looks like everyone who's anyone in the Los Angeles area physics community has shown up!" Sheldon said. "Even some other fields are represented. Look! There are those fools from the genetics department. What do they think they're doing here? It's like a couple of kindergartners trying to take a college science course."

Amy pursed her lips at him. "Sheldon… genetics is a form of biology. _I'm_ a neuroscientist. That's also biology."

"What's your point?"

She sighed. _It's no use._ "Nevermind."

Sheldon seemed satisfied. He continued looking around the crowded lecture hall.

Finally, the lights dimmed and a man walked out on stage to introduce the speaker.

Sheldon let go of her hand and joined the rest of the audience in a round of applause.

Amy's palm immediately felt strange and cold. She picked it up and lightly clapped along. She glanced over at Penny, who was mimicking the crowd, but was obviously uninterested.

After clapping, Sheldon didn't return his hand to Amy's. He leaned forward and placed his cheek on his fist. He was already entranced.

_Oh, to be a glove upon that hand!_ Amy thought, channeling her inner Shakespeare.

Penny feigned a dramatic yawn and Amy couldn't help but snicker, which earned her a scowl from Sheldon.

"We'll begin tonight with a question," the speaker started. "A question that is the drive behind all scientists of all fields. A question that will most likely never be answered, but we – as scientists – continue to try. That question is: 'Why?' - Our unquenchable thirst for the answer to 'why' is what compels us forward."

The speaker paused for dramatic effect. Amy could feel Sheldon almost shuddering with anticipation and excitement.

"We'll discuss one of the 'why's' tonight," the speaker continued. "Why do the laws of physics break down at the Planck scale?"

Amy yawned – a real yawn. She enjoyed physics, but she didn't want to listen to an hour of it. If it had been a lecture on the hippocampus or cognitive mechanisms, she would have been sitting on the front row, center stage. But quantum mechanics wasn't her cup of tea. Besides, she already knew all she needed to know about the Planck scale.

She allowed her mind to wander once again to the conversation between Sheldon and herself earlier that night.

Her boyfriend had already begun living up to his promise. He had held her hand all night with nary a complaint. In fact, he had been the one to initially take her hand in his. True to his word, he was moving forward. Baby steps.

Now, it was her turn. Her mother would be arriving back in California tomorrow. It was time for her to finally sort all this business out between two of the most important people in her life.

_"Ouch!" _A sharp pain shot through her side as Penny elbowed her.

Amy glared at her friend with a furrowed brow. Penny obviously didn't know her own strength.

_"Penny!"_ Amy whispered. _"That hurt!"_

"Sorry!" Penny said, forgetting to whisper. A harsh "_SHHHH_!" came from Sheldon, and Penny scrunched her face as though she was a little girl whose hand had just been slapped by her dad.

_"What do you want?"_ Amy whispered.

_"Look!"_ Penny pointed to something across the auditorium behind Amy.

She followed her friend's finger to a darkened part of the room.

_"What?"_ Amy squinted.

_"Isn't that your friend? Blake?"_

_"Who?" _Then Amy saw him. His clothes were nicer than any she had seen him in before, and his hair was combed and in place for the first time since she had met him, but it was definitely him.

_Ben_.

_"Would you two hens quick your cackling?"_ Sheldon was glaring at them.

Amy and Penny quickly turned back around to face the stage. Penny immediately pulled out her cell phone and began playing some tetris-like candy game that she'd become addicted to recently.

Amy stole another glance back at Ben. He looked completely on edge, which was not atypical for him, especially for such a crowded place. _I guess it makes sense that he's here. He is a scientist, after all._

Then, Amy noticed the blonde curly hair of the person next to him. Based on the way she kept throwing smitten glimpses up at Ben, Amy deduced that this woman was his Claire. And he was right; she was absolutely infatuated.

Amy looked up at her own boyfriend. The lights from the stage reflected in his eyes. He was completely enraptured with whatever the speaker was saying. Sheldon looked so much in his element, and so… sexy.

_Should I introduce him to Ben?_

Ben hadn't noticed Amy yet, so it was entirely possible that she and Sheldon could sneak out without running into them. That would save her from a potentially awkward situation.

_But, perhaps they should meet? It might help Ben to meet Sheldon, _Amy thought. She wasn't sure how her boyfriend would react, though. He never made very good first impressions.

She hadn't realized that she was still staring at Sheldon, until he looked down at her. He must have felt her watching him.

Their eyes met, and Amy's breath caught in her chest as he leaned in to whisper in her ear.

"_You aren't paying attention_," he said.

Amy smiled. _"Sorry_," she whispered back.

They both turned their attention back to the speaker. Amy did her best to listen for the rest of the lecture, and was only interrupted once when Penny shouted "YES!" after beating her high score on her game.

When it was over, everyone stood and gave the man a round of applause. Amy felt slightly guilty for never actually catching the speaker's name.

"That was just amazing," Raj said. "I'm so glad I came!"

Leonard and Sheldon nodded in agreement.

"Would have been better if Leonard could have kept Penny in check," Sheldon said.

"Hey! I'm right here!" Penny exclaimed.

"Yes, I know. You were so loud during the speech that I think the whole auditorium knows where you are."

"Alright, Sheldon, that's enough," Leonard helped Penny with her shawl and handed her handbag to her. She snatched her purse out of his hands, but held a steady glare on Sheldon until Leonard forced her to turn away.

"We've got to go, Penny," he said.

Reluctantly, she followed him out of the row.

"Bye, Ames!" she shouted without looking back.

"Bye!" Amy watched Penny shuffle toward the exit behind Leonard and Raj.

"Honestly, Amy, I don't know how you managed to become friends with someone with such a complete disregard for science," Sheldon said.

"Oh, she more than makes up for it in other areas," Amy replied as she gathered her purse. "And she was your friend first."

Amy looked back and noticed Ben and Claire waiting in a line for the exit.

Quickly, she grabbed Sheldon's hand. "Come with me."

"Where are we going?" he asked. "There's obviously a line. Why don't we just wait?"

Amy didn't respond. She dragged Sheldon along behind her, weaving in and out of other people, until she ended up right next to Ben.

"Ben!" She said, feigning surprise, as though she had just noticed him.

As he turned to look at her, Claire grabbed his arm and pulled herself in close. He winced at the contact.

"Amy!" he said with bewilderment. Amy was much happier to see him than she thought she would be after what had happened.

"Who's this?" Claire asked. Her voice was soft and sweet, but had a hint of possessiveness in it. Amy just smiled at her, and pulled Sheldon in close. She didn't want Claire to think she was after Ben.

"This is Amy," Ben said.

"Well, yes, you just said that," Claire responded. She held out her hand, and Amy took it.

"Hi, I'm a friend of Ben's," Amy said. "You must be Claire."

Claire nodded. "Ben has mentioned me?" She stared up at him with absolute joy.

Ben rolled his eyes at her. "Yes. You are part of my social group, so it stands to reason that your name would come up on occasion. Amy is a fellow scientist. She works in neurobiology."

Amy noticed that Ben didn't mention the study. She didn't know if it was because he hadn't told Claire about it, or if there was another reason.

Sheldon coughed to get Amy's attention. "Amy, you're hurting me."

She looked down and realized she still had a death grip on Sheldon's arm. "Oh! I'm sorry!"

She released him and introduced him to Ben.

Neither of them held out a hand to each other, but Ben studied Sheldon with what appeared to be a hint of admiration.

"Sheldon, this is Claire, Ben's…" Amy hesitated. She realized she didn't know how to introduce Claire. Her eyes darted to Ben for guidance.

"Girlfriend," he said. Claire gazed lovingly up at him again, still clinging to his arm.

Amy and Ben exchanged a knowing look. So, he had finally asked her out. _Progress is being made for everyone, it seems._

"Amy, we should arrange a double-date!" Claire said cheerfully. "I'd love to get to know Ben's friends." Amy knew that feeling. She remembered after Sheldon asked her out, she wanted so much to do the typical dating things that she'd seen normal couples doing her entire life. Double-dating included. Sheldon had never obliged.

_Well, maybe he will now_, she thought. _And we can help get Ben and Claire off on the right foot._

Ben and Sheldon both looked at each other in horror, but neither of them spoke up.

"Umm…" Sheldon began.

Amy took his hand. "We think that's a great idea!"

"We do?" He looked down at her in shock.

"Yes," she replied. Her eyes didn't leave his. She leaned closer to him. "A double date would be a great way to start moving forward," she said quietly.

"Well, our next date night isn't for a while, now."

"I think we can make an exception," Amy said.

Sheldon looked absolutely horrified. He pulled his hand out of hers and leaned in even closer to whisper in her ear.

"_Amy! I agreed to move forward, but we don't even know these people! We can't change our entire schedule. If you are that desperate for a double-date, why don't we just hang out with Leonard and Penny one night?"_

Amy just patted his shoulder and ignored his question, turning back to Ben and Claire.

"A double-date will be great." Amy dug into her purse and pulled out one of her business cards. "Here you go, give me a call any time to make the arrangements."

Ben took the card. "You… you're still in the same office?"

Amy understood what he was really asking. He, of course, knew that she had been removed from the study, and she knew that he felt guilty about the whole matter.

"Yes. Same office… just… different work."

"Oh." He put the card in his pocket and looked at the floor.

"Ok, well, we're leaving now," A frustrated Sheldon grabbed Amy's hand again and pulled her past Ben and Claire.

"Bye, you two!" Amy waved as she was tugged along, disappearing into the crowd.

* * *

**Chapter twenty coming soon!**

**Notes:** Please review! Constructive criticism also very much appreciated!

Your comments are what keep me going. :o)


	20. Chapter 20: The Maternal Meltdown

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 20: The Maternal Meltdown**

* * *

Amy leaned her head back against the glass wall of the airport's lost luggage office. She and her mom had been there for the past half-hour trying to sort out what had happened to the bag that her mother checked.

"I don't understand how it can just _disappear_," Carol argued with the employee.

_I would hate his job_, Amy thought. _You only hear complaints. Nobody just walks into the lost luggage room simply to say 'keep up the good work in here'._

TSA security agents were one thing, groping people willy-nilly, but this poor boy looked fresh out of high school and had a fear in his eyes comparable to a high-seas stowaway forced to walk the plank.

And her mom wasn't making it any easier. Amy would have to come to the employee's rescue. She stood up and sauntered over to the counter.

"Sir," Amy began. "You'll send the bag to our home free of charge once it arrives, correct?"

"Of course!" He nodded quickly, his eyes darting between the two women.

Amy turned to her mom. "Mother, I think that's the best we can hope for. Let's just go home. I'm sure you're tired after your flight."

Carol said nothing, and continued to glare at the employee.

"Is there anything in your bag that can't be replaced?" Amy asked.

Her mom shook her head. "I suppose not."

"They have our phone numbers, lets just go and let them do their job."

Carol shoved her wallet into her purse and slung the bag over her shoulder. "Your management will be hearing from me," she threatened as she stomped out the door.

The employee – Henry, according to his nametag – mouthed a silent "thank you" to Amy.

"Don't mention it," Amy said. "I've dealt with her disappointment my whole life. And I wouldn't be too concerned about her contacting management either. She's easily distracted. One time I just had to briefly mention that I had lost my virginity and she forgot all about my boyfriend issues."

She turned to walk away, but realized that she may be leaving Henry with the wrong impression.

Amy quickly spun around and added, "It wasn't true, of course… about my virginity. Still very much intact. I'm not a floozy."

Amy smiled at him, and then hurried out the door after her mother, leaving Henry wide-eyed at the lost luggage counter.

Once they had settled into Amy's car, Carol began to unleash a slur of complaints against about the airline.

"Never again," she argued, forcefully snapping her seatbelt into its holder. "I'll take the bus… or even the train, if I have to."

Amy smiled at the mention of trains.

"Something funny?" Her mom threw her an accusatory look.

"No, sorry," Amy said, biting her lip. "It's just… Sheldon loves trains. He'd prefer a train over a plane any day."

Her mom narrowed her eyes at her before transferring her gaze out the window.

"Well, that's _one_ thing we have in common, anyway," she said.

Amy sighed. "You'd have more in common if you would talk to him once in awhile," she argued.

"I'm not just going to call up your boyfriend for a chat, Amy. I don't even really know him. We have nothing to talk about."

"Oh, sure you do. So long as you don't say anything bad about physics… or trains… or comic books… or Doctor Who… or Star Wars… or Star Trek, you'll be fine!" Amy grinned at her mom, who was giving her a look that was eerily similar to Sheldon's classic expression of haughty derision.

"Don't knock it 'til you try it," Amy continued. "While you were gone, Dad got to know him pretty well. He likes Sheldon. They hang out all the time."

"That's different. You're dad is doing some sort of business venture with your 'boyfriend'." Amy frowned at her mom's use of air-quotes to describe their relationship status. "Which is something that I advised him against, I might add," her mom continued.

Amy was starting to fume, but she didn't want to get into shouting match with her mother - not so soon after she had returned to California. _She's just on edge after her lousy flight_, Amy reasoned. _She doesn't mean it._

"What is it about Sheldon that you don't approve of, exactly?" Amy asked.

"What do you mean?" Her mom batted her eyes innocently. "I don't mind him. I just don't think that your dad should be working with him is all. It's not a good idea. I mean… what if you two break up? Then what? He has all this time and money invested in him."

Amy couldn't believe what her mom was saying. She hadn't been back in town an hour and she was already talking about them breaking up. Her mom had never been this vocal about their relationship before. In the past, her qualms had been limited to just the tone of her voice or the occasional off-hand remark. But this? This hurt.

_It's time to up the ante,_ Amy told herself. She had promised Sheldon she would settle this ordeal with her mom, and she intended to hold to her promise.

"Mom, don't act so innocent. You can't expect me to believe that you approve of Sheldon." Amy forced herself to stay calm. It was important to maintain a rational conversation if she was going successfully win her mother over, but she was becoming increasingly angry.

"This all started way before this business with him and dad," Amy argued. "For some reason you just _don't_ like him. You never have."

Her mom's jaw dropped in disbelief. "Of course I do!"

"Oh, please. Be honest with me here. You haven't warmed to Sheldon since that unfortunate incident the first time you spoke via Skype."

Carol blushed at the mention of that ill-fated conversation. "Yes. That was a bit… unnerving."

"I've explained that to you numerous times, though," Amy said, as she hit the blinker and turned her car onto Los Robles. "You know that call was a farce."

Her mom nodded and sighed.

"Amy, its not that I don't like Sheldon," Carol said, a softness working its way into her voice. "Its just… this is your first boyfriend, and based on what I've seen of your time together… well… I just don't know that he is as invested in your relationship as you appear to be."

_So that's what she was so afraid of? That I might get hurt?_

Amy noticed the flashing lights of an ambulance heading her way and pulled to the side of the road to give it enough room to pass. Once the car stopped, she twisted in her seat to look at her mother.

"Mom…" Amy tried to think of a way to explain the intimacy involved in her relationship. She struggled to find something she could offer as proof of Sheldon's affections toward her, but couldn't come up with anything. Not anything that her mother would understand, anyway.

The silence was almost deafening.

"You can go now." Her mom said without looking up.

Amy glanced toward her review mirror and saw that the ambulance had passed them and was rounding the corner toward the medical district. She released her foot from the brake, and pulled back onto Los Robles. A few moments later, they arrived at the parking garage next to her mom's – and Sheldon's – apartment building.

After turning off the ignition, they once again sat in uncomfortable silence in the car.

"Mom…" Amy finally spoke up. "Sheldon and I… we are different."

Her mom nodded and rolled her eyes. "That's for sure."

Amy frowned at her. "But, our relationship is just as real as anyone else's. Sheldon is the one for me. We were meant to be together."

Her mom's eyes widened. "Amy, I think that's a little premature. I haven't heard him say anything _remotely_ similar about you. I just… I don't want him to break your heart. Men can be jerks, Honey."

Amy fumbled with her keys, still racking her brain to come up with something to allay her mother's concern.

"Sheldon was right about one thing, though," her mom said.

Amy looked at her inquisitively.

"He said that you were like him."

"I don't understand, Mom," Amy's eyebrows furrowed in confusion. "You've given me every indication that he isn't right for me. Why do you think we are the same?"

"You forget that I raised you, Amy," her mom said with a smile. "I got to watch you grow… watch you learn… watch you get too smart for your own good. I had to deal with your pretentious attitude toward others, had to calm down angry parents after you informed their children that they were 'to dumb' to participate in the science fair."

Amy blushed and looked at her lap. _Wow, I was more of a bully than I thought I was_. Her whole life, she had always claimed 'victim' in that area.

"But, Amy," Carol said, "I wouldn't trade any of it for anything. I am so very proud of how smart you are; And all that social stuff… well… you're just a late bloomer. I thought that if you had a boyfriend, it would 'fast-track' you in that department."

_What? This whole time she was playing matchmaker so that I would become more socially aware? _Amy frowned. She didn't like this. She didn't like it one bit.

Carol noticed Amy's frustration and held up a hand in surrender.

"I know, I know," she said. "You have every right to be mad at me. But you'll understand one day, when you have kids."

_I guess she's right,_ Amy thought. _Having a genius in the family does come with some baggage, I suppose. Mom just wanted a little normalcy._

"Anyway," her mom sighed. "My point is that you have made progress. You are definitely blooming, Amy. Believe me, I can tell. But, Sheldon… he seems a lot like you were a few years ago. You didn't _want_ a boyfriend. You weren't interested in relationships. I have a feeling that he is the same way. If he is anything like you were back then, I sense that his feelings for you don't match yours for him. And what if he _never_ feels that way?"

Of course her mom wouldn't be aware of Sheldon's feelings. It wasn't as though he publicized them or shouted his affections from the rooftops.

In fact, he had never even admitted as much to Amy – even in private.

_Why am I so confident in his feelings for me, then?_ Amy wondered.

She was, of course, convinced that he felt the same way she did. She was just sure of it. After everything they had been through together: the dates, his thoughtful gifts, the meaningful eye contact and handholding, the results of their experiment, his willingness to move forward… it all was evidence of his feelings for her.

_Wasn't it?_

But, what if her mother was right? What if Sheldon never got to a place where he could tell her how he felt? Or worse… what if her beliefs about his feelings were wrong?

Amy's confidence began to wane. Maybe all the progress they had made was only because she had been pushing him… _forcing_ him into a situation that he would rather not be in. Forcing him to prove himself. He already admitted that he felt he had to prove himself by kissing her, but he failed. Maybe she was too love-struck to see reality.

_No. Sheldon likes being pushed_, Amy reasoned with herself. _That's what he said_. Besides, the charts proved it! That's irrefutable scientific evidence.

Sheldon didn't have to say anything for Amy to know how he felt. She understood that he cared for her, and that's all that mattered. _I just need to be patient, like Sheldon requested._

Then, a realization hit Amy.

Her boyfriend had never admitted his feelings to her, but – then – _she_ hadn't admitted her feelings to _him_ either. Sure, she had subtlety hinted at a future with him, and commented about how she wanted more. But she'd never told him the whole truth. She'd never confessed the extent of her love for him.

_Would it matter? Would it change anything? Would he say it back? Would he be happy? Would he be scared? Would he run away?_

Amy had to know. She had to find out.

The sound of the car door opening snapped her back to the present. She glanced at her phone to check the time. How long had she been lost in her thoughts?

She got out of the car, clicked the remote lock on her keychain, and then trotted to catch up with her mom.

"You'll see, mom," Amy smiled. "Sheldon will surprise you." _I hope_.

They walked up the stairs mostly in silence. Amy hugged her mom as she left her at her apartment, and then continued up the stairs to 4A.

She knocked on the door, but nobody answered. She waited a moment, and then tried again.

Still nothing.

Amy leaned her ear against the door to see if she could hear any movement inside, but just as her head touched it, the door popped open. A disheveled Leonard greeted her.

"Amy! Hi!"

She looked him over. He was wearing a robe, even though it was still early in the evening, and his glasses were slightly askew.

"Is this a bad time?"

"Ummm…" He peered back into the apartment, then sighed and looked back at Amy. "No, its okay. Come on in."

Amy entered the apartment and glanced over at the couch. An equally disheveled Penny sat curled up in a blanket.

"Oh! Hey, Ames. We weren't doing anything! Just… you know... hanging out."

"I see," Amy said knowingly. She glanced between the two, and winked at Leonard. "So I guess Sheldon isn't around?"

"No," Leonard said, blushing. "I thought maybe he went to your apartment."

"Why would he do that?" _Sheldon hadn't mentioned that he wanted to come over. _She pulled out her phone to check her messages. There were none.

Leonard shrugged and sat down on the couch next to Penny, who cuddled up next to him. "Who knows? I can never keep up with what that wacko is doing. I heard him say 'bye', and I didn't ask questions. So long as he doesn't ask me to drive him anywhere, I don't care what he does."

Penny elbowed him. "He's your friend! You should care what happens to him! It's like losing a puppy dog. We might need to start printing out missing person posters and staple them to telephone poles!"

"Relax! He's probably just down at the comic book store."

There was another knock on the door and Leonard jumped up.

"_Man! A guy can not catch a break!"_ he muttered under his breath.

He walked to the door and opened it.

Bernadette was on the other side with two bottles of wine. She waived them at Leonard. "Impromptu girls' night!" She said with a huge grin. "Where's Penny?! She's not at her apartment."

"In here!" Penny shouted.

Bernadette pushed past Leonard, who closed the door and leaned against it in frustration. "_You've got to be kidding me_," he muttered.

"Amy! Good! You're here too! I was just about to text you!"

Amy clapped in excitement. She was in desperate need of a good girls' night.

Then she remembered her missing boyfriend. _Is he waiting at my place?_ She decided to call and check.

"Just one minute. I have to check in with Sheldon."

"Oooooo…." Bernadette mocked. "You have to check with your _boyfriend_. You two sound like an old married couple!"

Amy wasn't sure whether her comment was meant to be a complement or a put-down. She decided to take it as a complement and smiled back at Bernadette as she dialed Sheldon's number.

It went to voicemail. _Curious_.

She texted him.

-_Where are you?_-

Amy looked back over at the girls. Penny was slipping her shoes on and following Bernadette to the door, while Leonard was sprawled across the couch looking absolutely dejected.

"You coming, Ames?" Penny asked.

"Yeah, did _Shelly_ say it was okay?" Bernadette snickered.

Amy shrugged. "He didn't answer. I suppose I can come over for a bit. I'll try to get in touch with him later."

_There's a lot I have to say_, she thought.

"Bye, Leonard!" The girls shouted in unison as they walked out the door.

Leonard grunted. His face buried in the couch cushions.

* * *

A bottle of wine later, the girls were updating each other on their lives, while Bernadette painted Amy's toenails. Some Hugh Grant movie was playing on Penny's muted T.V.

Amy had just filled them in on she and Sheldon's recent date-night progress, leaving out her uneasy feeling after the conversation with her mother.

Bernadette and Penny listened with their jaws practically on the floor.

"_I KNEW IT!"_ Penny shouted. "I _knew_ something had happened between you two when we were at that god-awful physics lecture yesterday."

Amy blushed. _She couldn't get anything by her bestie._

"This is amazing, Amy!" Bernadette said, as she finished painting Amy's toes and twisted the cap onto the polish. "The tin man has a heart!"

"He's always had a heart," Amy said, slightly offended. She wiggled her toes, admiring the new pale nude color.

"Yes, but now its out there for the world to see!" Bernadette said.

_Oh no!_ Amy immediately felt a sense of panic. Maybe she shouldn't have said anything. If Penny or Bernadette mentioned something to Leonard or Howard, Sheldon would never hear the end of it. If he was mocked, he'd probably regress... and he certainly wouldn't be as receptive of her feelings for him.

"No, no, no!" Amy said quickly. "It's not out there for the world to see! Just for me! You can't tell anyone anything. Sheldon doesn't know I told you this. He _can't_ know I told you!"

"Ok, ok," Penny said, holding up her hands. "We won't say anything." She leaned over to pick out the polish she wanted Bernadette to paint onto her own toes.

"Awww, please, Amy?" Bernadette begged, as Penny handed her a bright pink-colored polish bottle. "You've got all the juicy gossip tonight!"

"No!" Amy said firmly.

Bernadette huffed and took another sip of her wine, before unscrewing the cap on the polish and scooting on her knees over to Penny's feet.

Relieved, Amy decided to change the subject. "Are you excited for opening night, bestie? It's coming up soon!"

"Yes! It is!" Penny gulped down the last of her glass of wine and began pouring herself some more. "I can't wait! I'm going to be a better Maggie than Elizabeth Taylor!"

Suddenly, a thought occurred to Amy. _Why didn't I think of this before?_

"Do you think I might, umm… get another pair of tickets?" Amy asked, as she fanned her toes with her hands.

Penny's face scrunched in confusion. "Sure, I guess. What for?"

"I have a friend who I would like to have come. And he'll probably want to bring a date."

"Is it the cowardly lion and the scarecrow?" Bernadette asked with a snort and a giggle.

Amy and Penny both frowned at their drunken friend.

"No. Its just… a friend of mine and his girlfriend," Amy said.

Penny eyed her curiously, but didn't press for any more information. "I'm sure I can pick up a couple more. I'll check with the theatre manager."

"Oh, I suppose I should also tell you girls…" Amy continued. "I got kicked off my project at work."

Penny practically spewed her wine across the room. "What?! _Again_?"

"Aww, Penny!" Bernadette said sadly. "Your toes!" Penny's jolt had pushed the polish brush across her foot, leaving behind a trail of bright pink paint. Bernadette grabbed a tissue and dipped it into the polish remover.

Amy sulked in her chair. She was all cried out over this. She had moved on. What's done was done.

"I don't want to go into it," she said. "I broke the rules and that's that."

"I don't see what you could possibly have done," Bernadette said as she wiped the extra polish of Penny's foot. "You're an amazing scientist."

"Thank you," Amy said sincerely. "But, like I said… I broke the rules. Without rules, these studies wouldn't be taken as seriously. I respect the university's decision… Even if I do think they're a bunch of no good, backstabbing – "

A dinging sound came from Amy's purse, alerting her that she had received a message. She waddled over to the bar stool where she had left her bag, moving carefully so as not to smear her freshly painted toes.

She pulled her phone out of her bag and looked at the screen. It was a text from Sheldon.

-_Call me.-_

She noticed she also had a missed call and a voicemail from him. _That's weird_, she thought. _I didn't hear my phone ring._

She played back the voicemail.

Halfway through it, her eyes widened and she dropped the phone.

"Oh no!" She cried.

Penny and Bernadette both looked up at her.

"What's up?" Penny asked.

"It's my dad! He's in the hospital!"

* * *

**Chapter twenty-one coming soon!**

**Notes:** So sorry for the long delay in posting the new chapter. An unexpected family visit, coupled with an increased workload at my job had me distracted for a bit. But, this chapter was extra-long to make up for it (I merged two chapters into one for you guys).

At any rate, I'm back, and I don't anticipate another lengthy delay anytime soon. *fingers crossed*

Please review! :o) Constructive criticism also welcome, as always!


	21. Chapter 21: The Infirmary Trepidation

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 21: The Infirmary Trepidation**

* * *

Amy nervously chewed on her fingernails and bounced her feet up and down in the back seat of Leonard's car. It seemed like they were catching every single red light on the way to the hospital.

Neither Penny nor Bernadette had been in a fit-enough state to drive her, having downed almost a bottle and a half of wine between them. Amy probably could have driven herself, but she was so on edge that Leonard worried she might get into an accident in an attempt to race to the hospital. He had insisted on taking her.

After what seemed like an eternity, they finally arrived at the hospital and Leonard pulled up beside the Emergency Room entrance to let Amy out.

"We'll find you after we park!" Penny called from the passenger's seat as Amy threw herself out of the car.

She ran through the doors of the E.R. and skidded to a halt in front of the reception desk.

"Where are you running to in such a hurry, missy?" The nurse crossed her arms over her chest and looked down at Amy as though she was a child in grade school who had been caught sprinting through the halls.

"My dad is here somewhere," Amy held her side, trying to catch her breath.

"Well, slow down… we don't want to have to check you in, too. What is his name?"

"James. James Fowler."

The nurse typed the name into the computer and rolled her finger over the mouse a few times.

_Why isn't she moving faster? _Amy tapped her fingers impatiently on the counter.

"4th floor," the nurse finally said. "But he's in surgery. You'll have to find a seat in the waiting – "

Amy didn't wait for the woman to finish her sentence. She took off for the elevator, practically falling over an elderly gentleman in a wheelchair.

"I'm so sorry, sir!" She called to the man as she hit the elevator button over and over again, willing it to move faster.

Finally, the doors dinged open and she jumped inside, punching the number "4" with enough force to almost break through the elevator wall. She caught a glimpse of the nurse helping the man compose himself in his wheelchair before the doors closed.

Once alone, Amy took a moment to catch her breath. She leaned against the hand railing and rested her head on the wall. She hadn't been able to get back in touch with Sheldon after listening to his voicemail, and he had been annoyingly vague in his message. All she knew for certain was that her dad was hurt in an accident of some sort, and it was bad enough to land him here… in the hospital.

The doors opened and Amy darted out, running straight to the nurses' desk. None of them looked up when she approached.

She knocked on the desk, but still received no response from the nurses.

"_Excuse me_?!" Amy was getting irritated. _How are these people responsible for dealing with the public?_

"Yes, ma'am? Can we help you?" One of the nurses finally looked up at her with frustration.

_Why is she annoyed? What could she possibly have to be irritated about? I'm the one whose father is in the hospital!_

"My dad is on this floor. James Fowler."

The nurse sighed and began clicking away at her keyboard.

"Yes. He's just come out of surgery. He's doing fine."

_Thank God! _Amy almost hugged the off-putting nurse.

"What happened?!"

The woman sighed and squinted at the screen. "Says here that he suffered a broken leg after a fall of some sort. My files really aren't that detailed. But the young man who brought him in could probably fill you in on what exactly happened."

The nurse pointed to a doorway with a sign overhead identifying it as the 'Family Waiting Area'.

"Can I see my dad?" Amy asked.

"In a little bit. They're getting him settled in to his recovery room. Just go wait for a doctor, okay?" The nurse pointed again to the waiting room, then indicated she was done with the conversation by returning to her paperwork.

Amy wanted to criticize the woman's people skills, but decided against it. Instead, she walked over to the family waiting area and cracked open the door.

Sheldon sat alone in the corner, looking uncomfortable. He had managed to squish himself into a ball as close to the walls as possible without actually touching them. His arms were tightly wrapped together across his chest and his eyes were gently closed. His mouth was moving, but no words were coming out.

_Probably reciting some noted physics journal from memory,_ Amy thought. She quietly watched him a moment before finally stepping into the room and closing the door.

His eyes popped open when the door shut and he jumped to his feet.

"Amy!"

"Hi, Sheldon."

"I didn't know if you were getting my messages. The cell service in here is horrendous."

"Yes, I did, but I couldn't call you back. It kept going to your straight to your voicemail."

Sheldon pulled out his phone and looked at it. "No service," he said, disgusted. "For a place where people might need to get in touch with other people urgently, this is unacceptable."

Amy nodded in agreement.

"I plan to write a strongly worded letter to – "

"What happened?" she interrupted, but Sheldon ignored her.

"Is your dad okay? They won't give me any updates since I'm not family. I've been stuck here in this room. Who knows what sort of airborne illnesses are moving about this place. I've probably been infected already." He pulled his coat up over his mouth.

"The nurse says he's okay. We can go back to see him soon."

Sheldon nodded, relieved.

"Sheldon, _what happened_?" Amy repeated a bit more forcefully.

Sheldon removed the coat from his face and looked at the floor. "You're dad… he fell. He fell down the stairs outside his apartment."

"What?! How?"

"The same way that any person falls, I imagine," Sheldon shrugged. "A loss of balance, coupled with a steep change in elevation. It's simple gravity. Though, what external factors caused him to lose balance, I'm not sure. We were at his place doing some work, and decided to take an ice cream break. We left the apartment and the next thing I know, he was tumbling down the stairs. Must've just lost his footing."

"When did this happen? Where's my mom?"

"Your mom? I haven't seen her. I've been here for at _least_ two hours." Sheldon hugged himself and looked around, as though he could see the bacteria closing in on him.

"How did you get to the hospital?" When she'd heard that her dad was here, she assumed that her mom was the one who brought him in. She hadn't even thought to stop at her mom's apartment to see if she was there.

"I called for an ambulance. I would've gone to get Leonard, but I didn't think it was wise to leave your dad with a broken leg in the hallway. He was unconscious."

Amy gasped. _Sheldon must've been so scared._

He noticed the panic on her face and grabbed her hand. "He's fine, though, right? That's what the nurse said?"

Amy nodded. She dropped his hand and threw her arms around him.

"Thank you, Sheldon," she said into his chest. "Thank you for being there for him."

Sheldon gulped and tensed for a moment; but then he relaxed into her hug and gently patted her back, pulling her in closer. "Of course. He's… he's like a father to me."

Amy blinked and pushed herself away in order to get a better look at his face. _Does he really think that?_

Just then, Leonard and Penny burst through the door, along with Amy's mom.

"Where is he?" Carol said in a panic. "I came as soon as the hospital called."

"He's fine," Amy said, grabbing ahold of Sheldon's hand again. "We're just waiting for the doctor. It's a broken leg from a fall. He'll be okay."

"Oh, thank God." Carol said, holding her hand over her chest.

Penny pulled Amy into a hug. "I knew it would be okay! I just knew it!"

Amy smiled at her friend, and then turned her attention to Leonard. "Thanks for bringing me up here, Leonard. I don't think I could have driven after all. And thanks for coming along, Penny."

"Of course! That's what best friends are for."

"Wait a minute," Carol said. "How did James get to the hospital?"

Amy looked up at Sheldon, and Carol followed suit.

"_You_ brought him?"

Sheldon shifted on his feet. "Umm... well, I called for the ambulance. I don't drive, as you know."

Carol stared at him a moment, then walked swiftly to him and threw herself around him, catching both Sheldon and Amy off guard. Sheldon coughed as Amy's mom tightened her embrace.

"Mrs. Fowler," Sheldon wheezed. "Mrs. Fowler, I might be infected with a virus."

Carol immediately let go of him and backed away.

"What?" she said, scanning him up and down. "What virus? Amy, did you know about this? Have you been checked?"

Amy, Penny and Leonard all rolled their eyes.

"No, Mom," Amy said. "Sheldon is delusional. He thinks he's contracted something just by being in this hospital."

"Excuse me!" Sheldon said, defensively. "I'm _not_ delusional. Things like that happen! Haven't you seen the movie _Outbreak_? Surely you have, it's got monkeys in it."

Carol laughed and wiped a tear out of her eye.

Leonard sighed. "You're _fine_, Sheldon."

A cough behind them caught their attention. They all turned to find a tall, bald-headed man with glasses holding a clipboard.

"Mrs. Fowler?" he asked.

"Yes?" Amy and Carol said in unison.

The man raised an eyebrow. "Are you the wife?" He was looking at Carol.

She nodded.

"I'm your husband's doctor. Mr. Fowler is ready to receive visitors now. He's fine, just resting. We had to put a rod in his leg to help with the healing process. He's in room 415, whenever you're ready."

"Thank you," she said.

The doctor left the room, and Carol turned to her daughter. "Honey, do you want to go in with me?"

"Of course!" Amy said, joining her mom by the door. They turned to look at the rest of the group.

"I think Leonard and I will just head home," Penny said. "I don't want to overwhelm him with too many people. You guys go on ahead."

Carol nodded, then looked at Sheldon. "Sheldon? Do you want to come back with us?"

Amy reached for her mom's hand. It meant a lot that her mom was making an effort to include Sheldon. _See mom_, Amy thought, _he's more than the robot that everyone thinks he is._

But Amy could tell her boyfriend was torn.

On the one hand, he had been in a hospital for several hours and was eager to leave, but on the other hand, she knew that he wanted to see her dad. _A man he considers to be like his own father_, Amy smiled at the thought.

Sheldon looked at the clock, then back to Amy and Carol.

"No, you two go ahead," he said. "Now that I know he's okay, I think I'll just get a ride home with Penny and Leonard."

"Suit yourself," Carol said. "And thank you, Sheldon. For everything you did today."

"Well, I certainly wasn't going to leave my girlfriend's injured father in the hallway," Sheldon scoffed. "What kind of boyfriend would I be?"

Carol smiled at him and squeezed Amy's hand. "Let's go."

They left the waiting area and walked down the hallway to room 415. Amy nudged the door open slowly, so as not to disturb her dad if he was asleep.

He wasn't. He was sitting up in his bed watching some old western program on TV. He grinned from ear to ear when he saw them.

"There're my girls!" he said.

"Oh, James!" Carol ran over to him and hugged him.

"Careful, honey," he winced. "Broken leg here." He pointed down to the cast-covered appendage, which had been elevated slightly with a few pillows.

"How was your flight?" he asked.

Amy realized that her dad hadn't seen her mom since she had returned to California. The accident must have happened just before they got to the apartment complex earlier that day.

That seemed like so long ago.

"My flight was wonderful," Carol said. She looked over at Amy and grinned. Her mom's airline woes certainly seemed minuscule now.

"Good to hear," James said. He peered around Carol to Amy. "Hey there, Button."

Amy stepped forward and held her dad's hand. "Hey, dad."

"Don't worry about me," he said, noting his daughter's concern. "It's just a broken leg. Happens to people all the time. It's a good thing Sheldon was there, though."

Carol nodded, and grabbed Amy's hand again.

"I tell you, Carol," James said. "Amy's got herself a winner with that boy." He winked at Amy, and she smiled back. She knew what her dad was doing. He, too, was trying to push her mom along.

_He's certainly waving the Shamy banner_, Amy thought. She quickly frowned at herself for using the phrase 'Shamy'. _Penny really is rubbing off on me._

"She may, indeed, James," Carol turned to Amy, tightening her hand around her daughter's. "I suppose we'll see, won't we?"

* * *

**Chapter twenty-two coming soon!**

**Notes:** Reviews and constructive criticism ALWAYS welcome! Thank you all so much for your continued support.


	22. Chapter 22: The Expansion Explosion

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 22: The Expansion Explosion**

* * *

"Aww, man! Come on! That's cheating and you know it!" Raj threw his Mystic Warlords of Ka'a cards down on the table in frustration.

"It most certainly is _not_ cheating," Sheldon insisted indignantly. "My card trumps your 'Sir Lance-alotta Zombies' card. Look!"

"But, Sheldon, the Wild Bill Witchkok card only works in the Wild West and Witches expansion," Leonard tried to reason with him. "We are playing the new Crypts and Castles expansion."

"Wrong, sir," Sheldon said. "Nowhere in the rules does it state that you can't mix expansion packs."

"That kind of goes without saying," Howard argued.

"Well, that makes absolutely no sense. How are we to know what's an official rule and what isn't?" Sheldon picked up the pamphlet with the game's guidelines and waved it around. "Why bother printing any rules at all if the players can just make up their own rules willy-nilly?"

Amy and Penny watched the boys in disgust from barstools in the kitchen and shook their heads at the group's childlike behavior.

"Its just a stupid card game," Penny said to Amy. "What's wrong with them?"

"It's like watching chimpanzees fight over the last banana at the zoo," Amy said sadly. "You just want to just squeeze your hand through the bars of the cage and offer them another banana to calm them down, but you risk losing your arm in the process."

Penny nodded. "_Anyway_…" She directed her attention back to the conversation at hand. "Amy, I wouldn't let your mom get into your head."

Amy had broken down and told her best friend about the talk she'd had with her mom in the car. She had to discuss it with someone, as it was becoming too difficult to keep bottled up inside.

"I mean, I let Leonard's mom into my head a few times," Penny admitted. "It was like she had cast some sort of spell on me. She dug deep inside and pulled out feelings that I didn't even know I had."

Her friend shuddered at the memory.

"And I pretended to be dating Leonard just to make my dad happy," Penny shook her head. "What was I thinking?"

"You're right," Amy conceded with a shrug.

"Parents have a way of manipulating their children," Penny continued. "Look at Sheldon's mom. I love her to death, but that woman has a hold over your boyfriend. She can make him do anything she wants. I'm not saying it's a bad thing - that man needs to be directed sometimes - but, don't let your mom do the same to you. You don't let her tell you who you can and can't be in a relationship with. You're a grown-up, Ames... sort of."

Amy smiled at her friend. Penny always made her feel more empowered.

"Well, after what happened with my dad, I think that Mom may actually be coming around," Amy said. It was true. Amy wasn't sure if it was just the stress of the situation, or if she had actually taken her daughter's conversation to heart, but Carol Fowler had certainly been more open to Sheldon at the hospital.

"That's great!"

"Yeah, but still - she definitely made me think... about a lot of things." Amy hesitated. _Should I tell Penny? _She bit her lip as she mulled it over.

"What's up?" Penny asked, obviously noting her friend's change in demeanor.

_I've already told her this much... why not?_

"Well, I've ... umm... I've decided to tell him how I feel."

"Who? Your dad?"

"What? No. I'm talking about Sheldon." Amy nudged her head in her boyfriend's direction.

"What do you mean '_tell him how you fee_l'?" Penny asked.

"Well... you know," Amy danced around her response.

"I know what?" Penny prodded.

"You know how much I..." Amy lowered her voice to just above a whisper. "_That I love him_."

Penny smiled. "Of course I do. It's easy enough to see. It's confusing beyond belief, and I don't understand it. But I do know that for whatever reason - you are without a doubt in love with Sheldon Cooper. _He_ may be oblivious to it, but us normal folk aren't."

"Well, I plan to tell him. Soon."

"Hmmm…" Penny looked over at Sheldon, who was red in the face and wildly waving a card around in his hand.

"Bad idea?" Amy asked. Not that it mattered. She'd made up her mind to do it already. She was going to tell him, regardless of her friend's advice.

"Well…" Penny looked at the cup of tea in her hand. "I don't doubt his feelings for you, sweetie. I mean, you heard what he told me in his apartment a few weeks ago."

"But…?"

"But I just don't know if telling him right now would be the best idea," Penny continued in a hushed voice. "Saying the 'L'-word changes things. Even if you both _feel_ it, you may not be ready to say it. Look at me and Leonard. I'm not saying I didn't feel the same way that Leonard did when he first told me that he loved me, but I just wasn't ready to admit it at the time. It put a real strain on our relationship. But, once you are _both_ ready, there's nothing better than telling each other how you feel."

Amy felt Penny's hand cover hers. The two sat in silence a moment before they were jolted by a loud bang in the living room. They twisted around to see that Raj had pounded his fist on the coffee table.

"No! Even if your card _could_ be played, Lancelot would beat Wild Bill hands-down!" Raj argued.

"Look at the cards' values, Koothrapali! Mine would obviously win!"

The girls sighed and once again turned away from the train wreck that was taking place in the living room.

"By the way, I got those tickets that you wanted," Penny said, changing the topic.

"Oh! Great! Thank you!"

Amy still hadn't heard from Ben about a double date. He probably had somehow talked Claire out of it. There certainly was a time when Sheldon could have talked her out of or into anything he wanted. Now, things were different. She took more risks than she had in the past, and so far – they were paying off.

_So far._

"Who are the tickets for, anyway?" Penny asked.

Amy hesitated. She hadn't told anybody the real reason behind her speedy departure from the brain wave analysis project at work. But she may as well rip the band-aid off. She couldn't hide it forever. Besides, she had already spilled her guts to Penny about practically everything else.

"They're for my friend Ben," Amy said.

"Ben? Really? I thought you couldn't see him outside of – " Penny paused as the realization finally dawned on her. "Oh. My. Gosh. That's why you were kicked off the project!"

Amy looked up at her with sad puppy eyes. She knew her friend would be able to put two and two together. Penny was smarter than she let on.

Penny leaned in to Amy. "_Does Sheldon know?"_ she whispered.

Amy shook her head. "Not yet. I haven't found the right time to tell him. He didn't even know Ben existed until the other day."

"Oh, Amy… you know how jealous your whack-a-doodle boyfriend gets…" Penny shook her head in disapproval.

"Well, there's no reason for him to get jealous," Amy shrugged. "It was a simple misunderstanding. Sheldon will understand."

"Since when has Sheldon ever been reasonable?" Penny gave Amy a 'get-real' expression. "Yesterday he made me go out and buy him a brand new toothbrush because his 'spidey sense' told him that I had touched his old one when I went to the bathroom. And he uses those crazy expensive toothbrushes, too! The thing looks like it was engineered by NASA or something."

Penny was right, of course. Sheldon had never been a sensible man. Case in point: the boys' current squabble.

Amy glanced back at the group in the living room and sighed.

"Your argument is ridiculous, Sheldon," Howard said. "You've _got_ to be joking."

"I'm not joking, Howard!" Sheldon exclaimed. "Although, I did hear a humdinger last week." He grinned from ear to ear. "Wanna hear it?"

"It doesn't matter," Leonard sighed. "You'll tell us anyway."

"You're right. So, Heisenberg was speeding down a road…"

Amy didn't listen to her boyfriend's joke. Her thoughts instead drifted to the events of the past couple of days. Penny was right - How could she have let her mom get inside her head like that? How could she have ever doubted Sheldon's feelings? Especially after all the strides forward they had been making together.

However, Amy would not be abiding by the latter half of her friend's advice. After all, if Penny had been open about her feelings for Leonard sooner, who knows where the two of them might be now? They could even be married already.

No. There was no sense wasting time. Amy knew what she wanted. She wanted to continue moving forward, just as she and Sheldon had agreed to do. Patience be damned. She'd already psyched herself up and was prepared to confess how she felt. How she _truly_ felt. She just needed to find the right time to do it.

The notion sent butterflies fluttering through her stomach.

Her introspection was interrupted by Sheldon's outburst of laughter as he led into the punch line of his joke.

"Sheldon, spit it out already!" Leonard growled.

"And Heisenberg says 'I don't know how fast I was going, but I _do_ know where I was'."

Sheldon busted into another fit of laughter, but nobody else joined in.

"Get it?" Sheldon was guffawing so hard tears were starting to fall down his cheeks. "_I know where I was_! Hahahahaha!"

Amy and Penny looked at each other with a confused frown, and Sheldon got up to get a tissue. His laughter echoed down the hall as he disappeared into his room.

The guys all looked at each other and sighed.

"You have to admit," Raj said. "It was kind of funny."

_That's it,_ Amy thought._ I've had enough of this._

She scooted off of the barstool and called down the hallway. "Sheldon! Come on! We have to go!"

"Where are you going?" Penny asked.

"We have to pick my dad up from the hospital. My mom will need the help getting him into the car. He's going to have a wheelchair and crutches."

Sheldon emerged from his room and padded down the hallway, the humor no longer in his face.

"Why do I have to go?"

"Because you promised," Amy said, collecting her purse. "And my dad will be expecting you. Plus, we could use the extra shoulder to help him up the stairs."

Sheldon sighed. "But, Amy! We haven't finished our Crypts and Castles game yet!" He stomped his foot in frustration.

"It's ok, Sheldon," Leonard spoke up, stacking all the cards together and returning the game to its box. "We're going to forfeit. You win."

Sheldon beamed. "I knew you'd see reason. Very well, Amy. Let's go."

Amy shrugged at the guys. "Sorry, guys. I think the only one who can beat Sheldon is me."

"What?" Sheldon said, offended. "When have you ever beaten me at a game?"

"I beat you all the time," Amy said. "I just don't rub it in your face. I feel like it's the girlfriend's job to spare her boyfriend's ego."

The guys snickered to themselves, and Amy turned to the door.

"Now, hold on a minute!" Sheldon exclaimed. "You can just make a point like that and then leave."

"We have to go, Sheldon," she said. "If you'd like, we can arrange a game of counterfactuals later. Or even this stupid Warlords of Ka game. I'm sure I can probably beat you at that, too."

"Its Ka'_a_," Howard corrected. "Why can nobody get that?"

"Oh, whatever," Amy said. "Come on, Sheldon."

Sheldon wasn't satisfied, but he followed his girlfriend out the door. "We'll settle this later, missy."

* * *

The ride home from the hospital was cramped. Amy, her parents, and Sheldon not only had to get themselves into Carol's tiny car, but also a wheelchair and a pair of crutches.

They managed to fit everything in, but only just.

As Carol drove, James filled the women in on the latest developments with Sheldon's games.

"The company loved it so much, they are going to fast-track it's production! There's apparently been a big push for puzzles and educational board games lately," James enthusiastically explained. "Research Lab is going to be marketed to the pre-teen age group and Sheldon's brilliant three-person chess game is going to be aimed specifically toward people like him."

"People like me?" Sheldon asked from the backseat. "You mean geniuses?"

"Precisely."

Sheldon grinned and settled back into his seat smugly.

"Of course, you know they had to remove the transporter piece," James continued. "And the catapult."

"And they're also taking out time machine and golf cart," Sheldon gave a disappointed nod. "I tell you what – their desire to make a profit is stifling my creativity."

"At least the beekeeper made it through, eh?" James asked with a grin.

Carol glanced between her husband in the passenger's seat and her rearview mirror, where she could see Sheldon and Amy seated quite close together. Amy had been forced to squeeze in beside Sheldon so that James' seat could be pushed back as far as possible to accommodate his cast.

To Amy's surprise, Sheldon didn't seem to mind her being so close. In fact, when she'd glided into the seat next to him, he had stretched his arm out across the headrest behind her. She knew it was simply to make himself more comfortable, but her heart swelled at the thought of his arms placed around her so casually.

She stole a glance up at him to gage how he was processing their position, but he was focused on his conversation with James… seemingly oblivious to his girlfriend's proximity.

_I love you._ She felt like saying it right then and there and just get it over with. This waiting was driving her crazy. Their closeness was making her want to be even closer to him.

She decided to push the limit a bit and quickly formulated a plan.

She timed her move to coincide with the car's next turn. _It's simple physics, _Amy thought. _Surely he'd understand that._ She used the force of the turn to fall nonchalantly into the nook under Sheldon's arm, and then relaxed into his side.

She felt Sheldon's breath catch as she bumped into him, and he immediately tensed. Amy assumed he was waiting for her to push herself back into place – but she didn't.

Amy refused to look up at him. She kept her eyes straight ahead. _If I meet his gaze, I'll chicken out and back away._

Eventually, Sheldon's breathing seemed to return to normal, but he was still tense. Amy chanced a glance at the rearview mirror. Sheldon was focused on the seat next to him and Amy in it. She could tell he was analyzing the situation, trying to figure out his next move.

_Will he push me away? _Amy began mentally preparing herself for it. She wouldn't be upset. After all, based on history, it was his most probable response.

Her dad was still carrying on about pricing and production dates for the games. He hadn't noticed that Sheldon's attention had been diverted.

Suddenly, Sheldon's eyes darted to the rearview mirror and locked on Amy's. She could feel panic momentarily shoot through her own eyes. She wasn't sure if Sheldon caught it, but neither of them looked away.

_Toughen up, Fowler_, she told herself. _Don't back down._ Her eyes still determinedly locked on his, she nestled further into his shoulder.

He narrowed his eyes at her slyly. He knew what she was up to. She knew that he knew. And he knew that she knew that he knew.

But, instead of wriggling away from her, he gave her a determined – almost competitive – glare through the mirror and dropped his arm down to her other side, pulling her in tightly.

_He doesn't want to lose_, she realized._ He thinks I'm playing a game._

Amy's eyes widened in shock, but she bit her lip and smiled in an attempt to keep the upper hand. She closed her eyes, settling into her boyfriend's shoulder and warm embrace.

_I'll take what I can get_, she thought.

As far as she was concerned, nobody else was even in the car. She heard nothing but her own thoughts and Sheldon's uneven breathing the rest of the way. It was music to her ears. Better than her harp.

Amy loved the fact that Sheldon had always been predictable. But _this_. This is why she was _in_ love with him - these rare moments of unpredictability. The ones where he surprised her.

But it all ended much to soon. Amy's eyes popped open as the car jolted to a stop. She frowned and looked at her mom. _This is your fault_, she thought. _You drove too fast._

As if she heard her daughter's mental accusations, Carol turned around to face Amy. She looked surprised to see the two of them wrapped around each other, but she didn't dwell on it.

"Alright, you two," she said. "Lets get going. This stupid apartment complex doesn't have an elevator. Who knows how long this is going to take."

Sheldon immediately pushed open his door and peeled himself away from Amy, who was still clinging to his side.

"Let go, please," he said. Amy looked down and noticed her hands were clinching the bottom of his jacket, preventing him from completely exiting the vehicle.

"Oh!" She dropped the fabric and scooted out of the car behind him.

Her mother was right. The trip up the stairs was indeed quite the endeavor. Amy and Carol managed to help James up to the apartment, leaving Sheldon to manage the wheelchair by himself. Unfortunately, the rest of the guys had gone to see a movie, or he would have been whipping them like sled dogs while they pushed the chair up the stairs.

Amy could hear the contraption banging against the walls as Sheldon dragged it up the steps to her parents' apartment. Once inside he opened the wheelchair and collapsed into it.

"James. That's it," Carol said. "We have to move."

"Well, dear," James cracked the seal on a can of Diet Coke and adjusted his leg on the couch, "We've got a couple of good options. Lets really put the pen to paper and figure it all out tomorrow. Believe me... now that I'm crippled, I am just as eager to leave as you. As it is, I have no desire to go down those stairs again until I'm all healed up."

"Why didn't you just leave the chair in the lobby?" Amy asked. "There's no need to have it up here. You'll only really need it if you are going somewhere, right?"

Sheldon groaned. "Well, its up here now. I'm not taking it back down."

"No, Sheldon," Carol insisted. "Of course not! You've done enough already. Thank you."

There was no denying it. Amy's mom was definitely trying. She still had a bit more opening up to do, but at least this was progress.

Finally, Sheldon stood - his legs a little wobbly - and pushed the chair to the nearest wall.

"I'd better be going," he said. "There's a Doctor Who marathon starting in about ten minutes."

Carol frowned at him, but James gave him an understanding nod. Amy laughed to herself. _I don't think my dad even knows what Doctor Who is._

"I'll head home, too," Amy said. She needed to get some time alone with her boyfriend if she was going to tell him how she felt.

"Later, Button," James said. "See you around, Sheldon."

"Thanks again, you two," Carol gently closed the door behind them once they were in the hall.

Amy took a deep breath. Finally, they were alone.

She rubbed her hands together nervously, and could feel her heart beating hard against her chest. _How will he take this?_ There was only one way to find out.

"Do you want me to walk you to your door?" Amy asked.

"Walk me to my door? What for? I'm not a dog."

"Let me rephrase my question," Amy said. "Would you _mind_ if I walked you to your door?"

"Well... I guess not. Seems like a lot of unnecessary exertion on your part, though." He shrugged his shoulders and began walking up the stairs with Amy following closely on his heels.

"Sometimes people walk their significant others to their door after an evening out," Amy explained. "It's not that unusual."

"I'd hardly call picking your dad up from the hospital an 'evening out'," he argued. "Though, based on the way you were grabbing at me in the car, we may as well count this as a date. There was certainly enough touching for it to qualify."

With each step, the weight of what she was about to reveal to him increased. She had no strategy for how to bring the topic up - she had just assumed she would wing it. However, as the moment drew closer, she regretted not having a plan.

"Thank you, by the way," Amy said, as they stepped onto the fourth floor landing. "For helping with my father, I mean. I know it was difficult. That wheelchair couldn't have been light."

"No, it certainly wasn't," he said as he reached his door and pulled out his keys to unlock it. "I think I'm going to have a rather large hematoma on my forearm for the next few days. Of course, I've always been prone to bruising."

_This is it_, Amy thought, as her boyfriend's apartment door popped open. _Now's the time._

Sheldon inspected the sore spot on his arm a little closer and sighed heavily. "The things people do for love."

Amy almost fell to the floor. _What? What did he just say?_

"Goodnight, Amy." He opened his door and turned back to her, waiting for her 'goodnight' in response.

_Wait… no… what did you just say?_ Amy thought the words, but her mouth just hung open like a fish. _Why can't you talk, Fowler?_

Sheldon wrinkled his forehead in confusion. "Amy?"

_You love me?_ Still nothing. No words. Just more idiotic gaping.

Sheldon shook his head. "Ok, well _you_ may have all night to spend walking people to their doors and generally acting foolish, but I have more important things to do. I'm going inside now."

He paused with his hand on the door, ready to close it.

"Goodbye, Amy." He waited once more for a 'goodbye' from his girlfriend. When none came, he again rolled his eyes. "You're being rude, Amy."

He shut the door in her face.

* * *

**Chapter twenty-three coming soon!**

**Notes:** Once again, I merged two chapters. I don't know why, but when I go back to edit, sometimes I feel like two chapters work better as one. Oh well!

Please review! Constructive criticism also very much appreciated! Your comments are what keep me going, even if you tell me what I can improve upon. It's the only way I'll get any better. :o)

Oh, and if you wanted to hear Sheldon's full joke, here it is (though, most of it was already in the story):

**_Heisenberg (the physicist) was speeding down the road and a cop pulled him over._**

**_When the officer approached his car, he asked, "Do you have any idea how fast you were going back there?"_**

**_And Heisenberg says, "No, I don't know how fast I was going, but I do know where I was."_**

… Fellow physics nerds will get it, _AmIRight_? *elbow nudge*

[crickets]

No good? ... Well, Sheldon and I thought it was funny. That's all that matters. Ha!


	23. Chapter 23: The Revelation Anxiety

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 23: The Revelation Anxiety**

* * *

"Amy?"

_Did Sheldon really just say what I thought he did?_

"Amy?"

_How could I not have said something back? I had fully intended to tell him how I felt. I could just kick myself!_

"AMY!"

Her train of thought was derailed by a golden-haired waitress in a Cheesecake Factory uniform.

"Penny?"

"Amy, are you okay? What are you doing out here?" Penny stood at the top of the stairs, with a bag of groceries in her arms. "Were you planning to knock or just stand there staring at their door?"

Amy looked around. She was still outside Sheldon's apartment. How long had she been there? She had no way of knowing.

"Oh…" Amy glanced back at the door. Sheldon was just on the other side of it watching his Doctor Who marathon. She could see the faint glow of the TV through the crack by the floor.

_The things people do for love._ He had said it. She was sure she hadn't made it up.

"Ohmygosh!" Penny dropped her purse and groceries on the floor and covered her mouth in shock. "You told him, didn't you?! What happened?"

"Told him?" Amy still couldn't think. She bent down to pick up her friend's frozen TV dinners and packages of ramen noodles that had spilled onto the floor, and began mindlessly tossing them back into the brown paper bag.

Penny grabbed her friend's arm and dragged her across the hall into her apartment, Amy precariously clinging to the bag of groceries as she was pulled along.

"Did you not lock your door?" Amy asked once they were inside. "That's really not very safe."

"What do I have that a thief would want?" Penny said, taking the sack of food from Amy. "They'd be awfully disappointed if they thought they were going to make any money stealing something from this place. Look! I even got the off-brand TV dinners." She waved one of the meals at Amy before cramming it into the freezer.

"I see." Amy studied her friend's belongings. _She's probably right. The only thing worth any substantial amount of money is the portrait of the two of us._

Her eyes drifted to a tiny silver bag that Penny had on her coffee table. "What's this?" Amy started to reach for it, but Penny ran over and snatched it away._  
_

"It's nothing!" Penny said. "Just... you know... a little something to keep things spicy between Leonard and I." She smiled and quickly went to put the bag in her room.

"Enough about me," Penny said when she emerged. She grabbed two bottles of water from the fridge. "Was I right? Did you tell him?"

Everything came flooding back to the forefront of Amy's memory.

"No." She plopped down on Penny's couch, disappointed in herself. It had been the perfect opportunity, too. _Why did I just freeze up like that?_

"What's wrong?" Penny sat down beside Amy, placing one of the bottles on the table in front of her friend. "What happened?"

"Nothing's wrong. Everything's… wonderful!"

"Huh? Why were you standing in the hallway all zoned out then?"

"Sheldon said that he loved me!"

Penny spewed water across the room.

"You're kidding!" Her eyes widened, and then she frowned. "Boy… I am really off my game, lately. You two never cease to surprise me. I thought for _sure_ Sheldon would take _years_ to get there. What did you say?"

"I didn't say anything," Amy said, throwing her face into her palms.

"What?! How could you not say anything! That's what you were wanting!"

"It just took me completely by surprise! I… I'm still in shock."

"Wowzers." Penny kicked off her shoes and pulled her feet up under herself. "So, you just… left him hanging?"

"Not exactly. I don't think he knew what he was saying," Amy admitted. "It wasn't like he looked me in the eye and said 'I love you, Amy'. It was more of a passing remark."

"Well, that makes it even better!" Penny said.

"How does that make it better?" Not that she was any less excited by what Sheldon said. Amy was glowing inside and out, and probably would be all evening.

"Well, if he had said it directly to you _with purpose_…" Penny held her fist to her chest in a dramatic fashion, channeling her inner actress. "If he had been all romantic about it, it wouldn't have been Sheldon. I would have thought something fishy was going on."

"Hey! He can be romantic when he wants to be."

"Oh, sure. Sheldon Cooper – a regular Romeo," Penny smirked at her. "Ames, you know what I mean. The fact that he said it in an off-hand way means that it is something he's at least _thought_ about. Usually, the things you don't mean to say are the most truthful of all. Like when I accidentally let it slip to one of my best high school girlfriends that her ridiculous clown makeup made her look like a slut." Penny held her hands up and shrugged her shoulders. "Oopsy."

Amy pondered Penny's hypothesis silently. Maybe she was right… or, the more depressing option, maybe Sheldon hadn't really meant what he said. _I'm probably freaking out over nothing, _she thought.

"But what the heck do I know?" Penny winked at her. "I've apparently lost my edge. Remind me not to participate in this year's Superbowl pool at work."

Amy smiled at her friend's joke, but her thoughts were already back on Sheldon. _What do I do now? Do I ask him about what he said? Do I just pretend like it never happened? Do I proceed with my original plan to tell him how I feel?_

"So – when are you going to say it back?"

Amy frowned. _It's like she's reading my mind._

"I'm not sure. I suppose I will just have to find another time when we are alone together."

"He's alone now. Leonard's at work doing some experiment with lasers, or light waves or something or other."

"No. Sheldon's watching Doctor Who. I don't want to interrupt him."

"Seriously?! You're going to let something important like this remain unsaid because your boyfriend is watching _Doctor Who_?" Penny's mouth hung open.

Amy nodded. She knew Sheldon better than anyone. He wouldn't want to listen to _anything_ if it interrupted something else he was so excited about – and a marathon of one of his favorite TV programs was definitely one of those things.

"Well… do you need any help getting some time alone with him? I can be sneaky and arrange some privacy for you two without Sheldon even knowing what's happening," she wiggled her eyebrows at Amy. "I can distract Leonard for a bit."

"I'm sure you could," Amy laughed.

"Hey – I can't help it that I'm so alluring!"

The girls laughed, but Amy shook her head. "No, this changes things," Amy said. "I'm going to actually have a plan this time. I don't want to be caught speechless again. I'll figure it out."

Amy sighed nervously. _I don't want to screw this up._

* * *

Compared to her personal life, the past couple of days at work had been relatively uninteresting. Rather than going to a study where she would take notes and make new observations, Amy was back in her own lab doing her 'same-old everyday brain stuff', as Penny called it.

_No big deal,_ she kept telling herself. _Cutting into this brain is just as exciting. _She wasn't being entirely sarcastic, either. She did enjoy her work.

Amy held her breath and leaned in close to her lab table.

She nudged her goggles up the bridge of her nose and steadied her hands over the brain in front of her.

She had been finding it difficult to concentrate during the day, as her mind kept drifting back to Sheldon. It was really becoming a problem. She'd already ruined three brain samples because she wasn't paying close enough attention to her movements.

She couldn't help it, though. Aside from a few text messages, she hadn't even spoken to Sheldon since Sunday, when he had told her that he loved her… sort of. Amy still wasn't sure he really meant it. And every time she had the chance to talk to him, she would spaz out.

He had called her a couple of times, but she didn't answer. It wasn't because she didn't want to talk to him – she did, desperately – but she didn't have her thoughts together yet. _What if he has realized what he said and wants to take it back_? No, she wanted to bring this up on her own terms.

Besides, every time she felt like picking up the phone to call him, she suffered from temporary, unexplainable mutism. She'd checked her vitals, but everything appeared to be in order._  
_

Meanwhile, her bestie was trying her hardest to get the two of them alone in the same room. The night before, Penny had lured Amy to her apartment under the pretext of having a girls' night. However, when Amy arrived, there was a note on her friend's door saying that she was over in 4A visiting with Leonard, and that Amy should meet her over there.

She knew what Penny was up to, of course. She paced the landing between the two doors for about ten minutes before she gave up and left. She just couldn't face him yet.

_I can't believe I'm the one freaking out here_, she thought.

"Knock, knock!"

Amy slipped at the unexpected sound of a cheerful voice coming from the hall. Her scalpel slid and lodged deep into the thalamus of the brain in front of her.

She groaned and looked toward the doorway. "Oh... hey, Hannah."

Hannah grimaced. "Oops! Sorry. I didn't mean to distract you."

Amy pulled her goggles off and tossed her latex gloves into the nearby trashcan.

"No… its okay," she sighed. "I had reached a stopping point anyway."

Hannah nodded. Her yellow glasses stood out against her bright, curly red hair, which she had pulled into a loose bun. Amy realized that it had been a long time since she'd really spoken to her former partner. She missed her.

"Fancy a lunch date?" Hannah practically skipped into the room and up to Amy's lab table.

"A lunch date?"

"Yeah… lets go down to the cafeteria and find a nice quiet place to chat. I hear the lasagna is _spectacular_ today." Hannah laughed at her own sarcastic remark and Amy couldn't help but smile.

"I don't know, Hannah," Amy said. "I got a lot to do here. I'm still trying to get back into the swing of things."

"Oh come on! What are you going to do? Eat here next to this brain?"

Amy shrugged. She'd done it before, after all. Why not?

"Oh, come on, Amy," Hannah nudged. "It's Wednesday!" Hannah donned a cheesy grin.

"Wednesday? What's so significant about Wednesday?"

"I dunno," Hannah shrugged. "It's hump-day?"

Amy frowned. Wednesday. _Had it really been three days since she had last seen Sheldon? _She couldn't remember the last time they had gone so long without seeing each other. _Darn nerves!_

"Why so glum, pal?" Hannah asked.

"Oh, I'm not glum," Amy said. "I've just had a strange week, is all. A lot of personal stuff going on that I am trying to figure out. Nothing bad, though."

"That's it. We're going for lunch." Hannah grabbed Amy's hand and started to drag her out the door. Amy gave in and giggled as she was pulled into the hallway, where she abruptly slammed into Hannah's back with a thud.

"Oh! I'm sorry!" Hannah apologized to someone in the hallway. She straightened up and moved aside, so Amy could see the reason they had come to such an abrupt halt. Ben was standing right outside Amy's lab.

"Ben?" Amy stepped toward him and Hannah let go of her hand.

"I'll see you in the cafeteria," Hannah said. She winked at Amy before trotting down the hallway and disappearing around the corner.

"Sorry to interrupt your work," Ben said.

"It's okay. I was just going to lunch."

Ben rubbed his arm nervously. "I … um… I lost your business card."

"Oh? I was worried that you didn't want to see me anymore. I thought maybe Claire didn't care much for Sheldon and I."

Amy had always prided herself on being delightful company, but she could definitely understand her boyfriend's peculiar mannerisms putting people off.

He shook his head. "No. In fact, Claire has been quite insistent that we follow up on this double-date idea. Though, I think that's just because she wants dote me around in public." He rolled his eyes. "It's like I'm a designer handbag or something."

Amy snickered. "She's just happy to be with you, I'm sure."

Ben didn't respond, and the two stood awkwardly looking at each other for a few seconds.

"So… is that why you are here?" Amy finally asked. "The double-date?"

"Yes. I suppose so. Though, I want my objection to the whole thing noted."

Amy grinned at him. _That's just what Sheldon would say._

"Noted," she said. "I was thinking that you and Claire might like to attend my friend's play, actually. The performance is this weekend."

Ben shrugged his shoulders. "That's as good as anything, I guess."

He obviously wasn't interested in the details. He was clearly only fulfilling an obligation to Claire, just as Sheldon would be for her.

_Women really are the dominant sex_, Amy thought.

"Ok. Well, here's another one of my business cards." She pulled one out of her pocket and handed it to him. "Give me a call later this week on my cell. We can make all the arrangements. We can plan to grab dinner before the show."

Ben nodded, silently staring at the card in his hand.

"Ok… well… It's a date!" Amy smiled.

Ben nodded again and turned to leave, counting his steps under his breath as he walked. Amy noticed he was also avoiding the cracks in the tiled floor.

"Bye, Ben!" Amy called after him. "Thanks for getting in touch!"

Ben paused and turned in place. "Thank you for your help," he said.

"Of course! This will be good. You know… for what we talked about at the deli. For your progress as a couple. Baby steps, remember?"

He didn't respond. He simply twisted back around and continued out the door.

Amy watched him leave. _He really is improving_, she thought. He wants this, even if he doesn't want to admit it.

Suddenly, a wave of calm came over her. She had a sense of peace about the whole situation with Sheldon. He loved her. She knew it. He'd already as much as admitted it, even if by accident.

_Suck it up, Fowler, _she told herself._ If you expect Sheldon to take such a big step outside of his comfort zone, then you have to be willing to do the same._

With a bit more confidence, Amy shut the door to her lab and hurried to the cafeteria to find Hannah.

She was pleased to have the chance to catch up with her coworker over lunch. Amy enjoyed the fact that even though she was no longer a part of an assigned study, she hadn't lost her friend. Plus, she was able to clear up all the rumors that had been floating around campus about she and Ben. Hannah had heard them all, of course. She didn't believe any of them, but she nevertheless took the opportunity to tease Amy a bit.

Amy had also learned that Hannah and Mark were unfortunately not able to work out their differences. The news was especially disappointing for Amy, because Hannah informed her that she had been planning to ask her to be in the wedding. Yet another opportunity for Amy to wear her tiara had slipped away.

The brief chat with Ben and her lunch with Hannah greatly improved Amy's mood for the rest of the day. She managed to get through her next brain sample without so much as a single mistake.

Immediately after work, Amy went straight to her apartment. She needed a few minutes to herself before she spilled her soul to the man she loved.

_The man I love._ It sounded so ridiculous to her ears, but she knew it was true. And in a few hours, she could – maybe – say with absolute certainty that she and Sheldon were _in love_ with each other. The thought made her weak at the knees.

She brewed herself a cup of tea, and set it on the table next to her harp.

Amy sat down at the instrument, gently gliding her fingers over the strings one by one. The notes sounded beautiful individually, but together, when she played a song, the music had the ability to transport her out of herself. She would become capable of transcending any thought that weighed on her mind.

But she didn't want that now. She didn't need to transcend. She wanted to bask in the glow that was the feeling of being in love.

She withdrew her hand from the strings, and leaned over to pick up her cup of tea. The warmth on her hands was calming… relaxing. After only a few sips, she stood to her feet and placed the still-hot beverage on her counter.

_Lets do this._

She gathered her things, shut her light off, and walked out the door.

* * *

_This is it… again._

Amy stood outside Sheldon's apartment, mentally preparing herself for what she was about to do.

She didn't have a plan before, so when Sheldon made his comment, she had been completely thrown for a loop. But now, she was ready. She had mulled it over long enough.

She reached up to knock on Sheldon's door.

No answer.

She could hear cheers coming from inside, so she knew that someone was home.

She knocked again.

No answer.

_Oh, screw it. I'm going in._

She opened the door to find all of the guys with PlayStation controllers in their hands. Sheldon was sitting rigidly in his spot with a look of intense concentration on his face.

Howard and Raj were jumping up and down with their controllers, as if their movements somehow helped their avatars react faster, and Leonard sat on the edge of his chair, clicking furiously at one of the buttons in his hand.

"Come on, come on, come on!" Leonard yelled.

"Take _that_!" Sheldon cried out, pressing firmly on one of his controller's buttons. An explosion sounded from the TV, and Howard threw his controller onto the floor.

"Sheldon! That was _me_!"

"Well, get out of my way, Howard!"

"But we are on the same team!"

"Doesn't change the fact that you were in my way."

"I was _covering_ you!"

"Mwahahahaha!" Raj laughed maliciously as he lodged a grenade at Sheldon, and blew him up.

Howard groaned. "If you hadn't killed me, I could have shot him before he threw that grenade."

Amy coughed to get their attention.

"Oh! Hey, Amy!" Leonard smiled at her.

"I'm sorry, I forgot it was Halo night," she said.

"It's okay. Raj and I just killed Sheldon," he grinned.

Sheldon tossed his controller onto the coffee table and stood up to greet his girlfriend.

"Hello, Amy!"

"Hello, Sheldon."

"What are you doing here? We don't have anything scheduled this evening."

"No, we don't. We just… haven't talked in awhile."

"Well, I've tried calling you, but you haven't answered," he said defensively. "You can't blame _me_ for us not conversing at a rate that meets your approval."

"Yes, I know that you've called. I have been busy at work. I'm sorry." She felt guilty lying to him. Though, it wasn't entirely a lie. She _had_ been busy.

"No need to apologize. I understand better than anyone that when you are in the middle of a breakthrough its best to just plow on through," Sheldon said. "And, yes. As you correctly observed, tonight is Halo night. You are welcome to watch, so long as you keep quiet."

"No thank you," Amy said. _Watching the guys play Halo? That sounds like a fate worse than death_. "Actually, there was something specific that I was hoping to discuss with you."

"Oh… ok, well perfect timing," he said. "It's break time. We just finished a game."

"You mean, Leonard and I just annihilated you," Raj pointed out.

Sheldon ignored him. "We have exactly eight minutes before the next round. Would you like a beverage, Amy?"

"No, thanks. I'd really just rather talk," she glanced over at the couch. Raj and Howard were staring openly at the two of them, making no attempt to hide the fact that they were eavesdropping.

"Can we… um… go to your room?" She asked, nudging toward the group in the living room.

Sheldon twisted his head to follow Amy's gaze. Howard and Raj quickly diverted their attention to the television and grabbed their controllers off the table, pretending to concentrate on the screen.

"I suppose so," Sheldon said. "We do have a lot of nosy-nellies here." He led Amy down the hallway.

"You kids use protection!" Howard called after them.

"You're the one who's going to need protection, Howard," Sheldon said without looking back. "I'm going to destroy you when we get back to our game!"

"We're on the _same team_!" Howard yelled, throwing his hands up in exasperation.

Sheldon opened his door for Amy, and she nervously walked inside.

There was a stack of new comic books in a plastic bag on his bed. _It must be new comic book night, too_, she thought.

He picked the bag up and hooked it onto his closet door, then motioned for her to take a seat on the bed.

Amy's heart started to pound as she sat down.

_This is really it._

"What do you wish to discuss?" Sheldon asked. "Is it about my monthly email blast? It has been pointed out to me that I probably shouldn't have mentioned the horrible side effects of the food poisoning that you contracted last month."

_I was in his email blast?_ Amy didn't even care what Sheldon had written about her, she was just excited that he considered her important enough to include.

"No, that's not it," she began. "I … um… I wanted to run something past you. And I want you to keep an open mind."

"Ok…" Sheldon said hesitantly. He shifted on his feet, and crossed his arms over his chest.

Amy glanced down at her hands in her lap.

"The other day… when we helped my dad home from the hospital… Something you said really made me think." She paused and looked up at him. He stood beside the bed, waiting for her to continue_. I wish he would sit down_, she thought. _He's making me more nervous._

"I say a lot of things that make people think. You'll have to be more specific."

Amy sighed. "You remember when I walked you to your door?"

"Yes."

_What am I saying? Of course he remembers. He remembers everything._

"You said that people do a lot for the people that they love."

"Yes," he nodded. "I remember the conversation. I don't forget things. For example… you were wearing a red top. And there was a hole in your skirt."

Amy frowned at him. "What do you mean there was a hole in my skirt?"

"Right about here," he motioned to a spot on his thigh, just above his knees. "I didn't say anything because I assumed you knew it was there."

"Of course I didn't know," Amy said. "Why would I purposely wear a torn garment?"

"I don't know. I thought it was some kind of fashion trend," Sheldon shrugged. "I see holey jeans all the time in stores nowadays. Though, why somebody would pay good money for clothes that look like they were run through a wood chipper, I'll never know."

Amy groaned loudly. This conversation was getting off-track.

"Oh, just forget about the skirt!"

"I wish I could," Sheldon said.

Amy sighed and rubbed her temple. "This isn't what I want to talk about, Sheldon."

He sat down next to her on the bed.

"Well, spit it out kiddo. I have a game to get back too. No doubt Wolowitz and Koothrapali have already redesigned my avatar."

Amy turned to him. _I'm just going to have to dive in and hope for the best here._

"Sheldon… do you love me?"

"Do I _love_ you?"

"Yes. Please tell me the truth."

She could tell that the question took him completely off-guard. He looked down at the floor, and his eyes darted around.

"I… I certainly care very deeply for you, Amy. You know that."

"Yes. I do know that. But you also care very deeply for your new Wolverine comic in that bag over there. I want to know if you _love_ me."

Sheldon nervously glanced over at the bag hanging on his door. Then, a look of realization flashed into his eyes and he crossed his arms over his chest again.

"Have you been talking to Leonard?" he asked, irritated. "What did he tell you? I swear… I'm going to have to give him another strike. No online class for him this time, no-siree. I – "

_Leonard? What has he been saying to Leonard?_

"No…" Amy interrupted. "I haven't talked to Leonard. Why?"

"Oh. No reason." He squeezed his hands together in his lap.

"What would Leonard tell me if I _had_ talked to him?" She prodded.

"Nothing." He began to twitch.

"Sheldon…?" Amy said his name slowly, like a parent asking their child who took the last cookie.

"How would you really know if you love someone?" Sheldon asked quickly, his words practically running together. "I mean, you can care about someone… sure… but there's no way to really tell if you _love_ someone. You can't scientifically prove anything other than monitoring hormone levels and brain patterns. Even then – "

"You love your mother, don't you?"

"Well… yes."

"And your MeeMaw?"

"Of course."

"Well, Sheldon…" Amy said. "Clearly, you are capable of love. Do you love _me_?"

He stared at her a moment, considering her question, and then he took a deep breath and began speaking very quickly again.

"There are different kinds of love, Amy. In fact, the Greeks have several words for the various types of love. 'Philia', for example, is the type of love you'd have for a friend… and 'storge' is the type of love that – "

"Sheldon! I don't need a Greek lesson right now!" _Geez, keeping this conversation on track is like herding cats._

Sheldon quieted down and bit his lip.

_Enough of this._

"I love you, Sheldon. There. I said it."

Sheldon's eyes grew wide. "When you say you 'love' me… do you mean the Greek's 'philia' or 'eros' or – "

"I mean _I love you_, Sheldon," Amy cut him off. "You drive me insane sometimes, but I love you. And you know exactly the kind of love that I mean."

"I see." He drew his hands into his lap and looked around his room.

Amy would give anything to hear what was going on in his brain right now. She was certain that his Vulcan hearing was picking up on her heart thumping loudly in her chest. It seemed to echo in the silent room.

"So…?" She asked.

Sheldon looked up at her, tentatively. "I… I don't know what you want me to say, Amy. I'm not very good in this kind of situation. You know that."

_This kind of … 'situation'? What does he mean by that?_

"Oh," her shoulders fell. "Ok. I just thought… after what you said…" Amy closed her eyes and breathed deeply. "So, you don't love me, then?" She had figured as much. She had already prepared herself for this response.

"Well… now hold on," he said, twisting to face her. "I didn't say that."

Amy's eyes popped open, and she turned to him. "So… you _do_ love me?"

"Well… I didn't say that either," Sheldon said, quickly looking away.

Amy frowned. "Well, what exactly _are_ you saying then, Sheldon?"

"Umm…"

Amy said nothing, waiting for his response. _He's not going to get out of this so easy. I want an answer... no matter what it is._

"Umm…" Sheldon repeated. "I guess… I guess..."

He frowned. "I've been trying, Amy."

"I know that." Of course she knew that. He constantly reminded her of it any time she brought up anything remotely venturing into the realm of feelings or the future.

"No," Sheldon said firmly. "No, you don't know."

Amy leaned away from him, startled by the hint of frustration in his voice.

"I've been trying. I've been trying for years. My whole life, even."

"We've only known each other a little more than three years, Sheldon."

He shook his head. "I'm not talking about _you_. I'm talking about _me_. Good Lord, woman."

Amy was now thoroughly confused. Sheldon sighed. "Amy, I am better than the average person. We both know that. You are, too."

She pursed her lips and nodded. She couldn't deny it. _When he's right, he's right._

"However," Sheldon continued. "The fact remains that I _am_ human. And, as such, unfortunately have the ability to fall victim to the unsavory torrent that is human emotion - something I've been trying to prevent my whole life. And let me tell you, it's hard work. Do you know how difficult it is to maintain such perfection? I've honestly been _trying_."

_Oh. _He had been trying _not_ to fall in love with her. Now she understood.

"You're making it even _more_ difficult, though. I wanted to remain a superior being... a man who's mind is untarnished by trivial human emotion. But, I am learning that is impossible. And... And... well... despite my best efforts... I suppose that I _may_ have become inflicted by emotions that _could be_ considered comparable to those you just expressed."

A grin slowly spread across Amy's face. "So then… you _do_ love me?"

Sheldon sighed, his shoulders fell as though someone had just figured out in two minutes the equation he had been working on all week. "Yes. Fine. I admit it."

"Could you say it, please?"

"Why?"

"Because it will make me happy."

He smirked at her. "Why don't you just get dreadlocks and I'll go buy a tie-dyed shirt from a local thrift shop? It'll be groovy, don't you think?"

"Fine. Nevermind." _Penny was right after all._ _He clearly isn't ready for this._ Amy stood up to leave. "Go back to your game, Sheldon."

"_OKAY_, okay…" Sheldon stood up, too, and grabbed his girlfriend's hand. "Amy… "

"Yes?" She cartoonishly batted her eyelashes at him.

He took a deep breath.

"I ... love you. Truthfully."

She beamed up at him.

"Oh, Sheldon!" She jumped into his arms and planted a kiss on his lips.

He briefly kissed her back, but then pulled away.

"Amy, now hold on a minute!"

"What? We love each other!" She tried to kiss him again, but he put a hand over her mouth.

"That doesn't mean I want to exchange saliva. Good grief. I don't do that with my mom or MeeMaw, and I love them, too. What would _they_ say if they saw us kissing here in my _bedroom_ of all places?"

Amy frowned at the image of him kissing his mother. And she really didn't want to think about his mom watching them kiss either, whether they were in his bedroom or not.

"But - you said yourself - there are different kinds of love," Amy argued. "Ours is different than it is with your mom or MeeMaw… isn't it?" _God, I hope so._

"Yes, it is. But love doesn't change the fact that I don't like unnecessary touching. Our relationship agreement is still in effect. This doesn't change anything."

"Oh." Amy stepped back and sighed. _What did I expect?_

_Actually… this is more than what I expected._ She decided to accept it and be happy. She grinned back at her boyfriend.

"Ok, Sheldon," she said with a smile. "I can work with that."

"Ok," he replied with a nod, a little surprised by her compliance. "Now… is that everything that you wished to discuss?"

She nodded cheerfully.

"Very well. Now that we've turned into full-on hippies…" he turned to walk to the door. "I'm going to return to my video game. I'd appreciate it if you didn't mention this to the guys. It's none of their business."

"Are you embarrassed by me?" She couldn't help but feel hurt. Leonard and Howard weren't shy about their romantic dalliances, and Raj wouldn't be either if the poor boy could keep a woman.

"That's ridiculous, Amy. Of all the females in our social group, you are by far the least embarrassing. Honestly, I don't know how Leonard even shows his face with the way Penny behaves most of the time."

"Well, then why don't you want them to know?"

"Because, I have to listen to them drone on and on about their love lives. I'd really rather not add to the ridiculous discussions. Besides, they will only taunt us... just like they did when we played D&D. Now, I implore you to ask yourself: Is that what you really want?"

_Drat. He's right._

"Ok," Amy smiled. "It'll be our secret." Somehow, the idea of a private love between she and Sheldon made it all seem a little more exciting.

"Thank you," he said, turning back to the door.

"Oh… and Sheldon?"

"Hm?"

"I love you." She gave him a toothy grin.

"I know."

She nudged him with her elbow and he sighed. "I love you, too."

Amy saw the corners of his mouth briefly turn up into a smile, but he caught himself and, with a nonchalant cough, quickly turned his expression to one devoid of emotion. He opened his door and walked out to the living room with Amy following closely behind.

"There you two are!" Leonard said. "We were wondering what was taking so long. Our eight minutes were up six minutes ago!"

"Well… based on the smile on Amy's face, I'd say there was no sex being had," Howard observed. "There's no way Sheldon could make a woman _that_ happy in the bedroom."

_That's not fair,_ Amy thought. Some of she and Sheldon's most romantic moments had happened in his bedroom, and she'd always left fully satisfied. Amy's smile dropped from her face and she glared at the tiny man. "For your information – "

"Amy, just ignore him," Sheldon interrupted. "And Howard… I'm going to wipe that ridiculous smile off your face in just a second. Get ready to be obliterated."

Sheldon picked up his controller.

"We're _still_ on the same team, Sheldon!" Howard argued.

"Irrelevant."

* * *

**Chapter twenty-four coming soon!**

**Notes:** You know the drill. I appreciate those reviews and critiques. Thankya in advance.

Also, there are only about 5 chapters left or so... depending on whether or not I opt to merge a few together like I've apparently taken to doing lately.

It's bittersweet, being this close to the end.


	24. Chapter 24: The Quarantine Anomaly

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 24: The Quarantine Anomaly**

* * *

"You're still coming, right? Tomorrow?"

Amy and Bernadette were perched on stools, sipping their frilly-looking alcoholic beverages while Penny wiped down the bar. Amy didn't even know what was in her drink. All she knew was that it was blue and fizzy and tasted like heaven.

It was Friday night and the girls' planned hang-out at Bernadette's apartment had been altered due to the fact that Penny had taken a late night shift at The Cheesecake Factory. Her play was opening the following evening, and she would be missing out on one of the restaurant's busiest tip nights. So, they decided to bring their girls' night to her work instead.

"Penny… _seriously_? Of course we are coming!" Bernadette squeaked. "Amy here has practically reserved a whole row between her own family and friends, and I've already told you umpteen times that I will be there!"

"I know, I know…" Penny said, filling a glass with draft beer for another customer. "It's just… this is really important to me."

Penny went to set the full glass down in front of a man wearing a business suit at the other end of the bar. He looked like he had just come from a meeting of some sort. He had his Blackberry out, and was clicking away at it.

"We know it's important for you, bestie," Amy said when Penny returned. "We wouldn't miss it."

"You don't understand… this is _really_ important," Penny insisted. The look in her friend's eyes peaked Amy's interest, but Bernadette asked first.

"What do you mean… _really_ important?" The blonde said, leaning in.

"Oh… you know… just… it's important is all," Penny shrugged. "It's opening night. I want all my friends there. You can't let any of the guys back out, either."

"Well, you can count on us," Amy said, not entirely satisfied with her friend's answer.

"You all have to come to the after party, too," Penny added.

"Why? Isn't the after party just for the cast?" Bernadette asked.

"No, it's for the cast, crew, and their families and friends."

"Well, I don't know, Penny. Ben and Claire will be with us. We are using your play as our double-date." Amy grinned, but her smile dissipated upon seeing her friends' horrified expression.

"What?! No! They can come too if they want!" Penny begged. "You _have_ to be there!"

Amy frowned. "Why is it so important? It's just an after party. Not that I don't want to spend time with you… but you'll have Leonard and your family there. And if the night takes a romantic turn for Sheldon and I, we'll want to rush home as soon as possible." She wiggled her eyebrows at her friends.

Bernadette grimaced at her, but Penny brushed Amy's comment off.

"It's just important to _me_, okay? I… umm… I want to introduce you to everybody. You're one of my best friends."

"Hey! What about me?" Bernadette said, offended.

"You and Howard, too," Penny smiled. "_Everyone_ has to be there."

Amy and Bernadette exchanged confused glances, but didn't press the matter.

"We'll be there," they said in unison.

"Thank you," Penny looked relieved. She began counting out coasters and stacking them up behind the bar. "So… double date, eh?"

"Yeah, you actually convinced Sheldon to go on a double-date?" Bernadette asked with a hiccup as she took another sip of her pink drink. "I can't believe it. Did you lure him in with the promise of a model train or a lifetime supply of Red Vines or something?"

"Oh, Bernadette, don't you know?" Penny mocked. "Sheldon would do _anything_ for the woman he _loves_."

"OOOOoooooo..." Bernadette sang. "That's right! He _looooovveees_ you."

Amy blushed. Her friends were so immature sometimes_._ "Come on. Try not to talk like that. You might accidentally let something slip around the guys."

"You know that one day the guys _will_ find out, right?" Bernadette asked.

"Yes. But I don't want it to be because of me," Amy said. "Besides… It's still new. Like one of your shiny new pair of shoes, Penny. We haven't had a chance to break it in yet."

It was true. Since Wednesday, Amy and Sheldon hadn't been alone together. Not wanting to spill the beans in front of the guys, the pair had opted for an awkward lingering stare at each other any time they left each other's company.

They both knew what the stare meant. _I love you._ Amy thought it was terribly romantic, but the added awkwardness didn't go unnoticed by the rest of their gang. For the most part, however, the guys ignored it. They were accustomed to Sheldon and Amy's odd behavior as a couple, and no longer asked questions.

Amy was proud of Sheldon. They were right on target to reach the four-year goal that she had plotted for their relationship right after they started dating. She had secretly doubted that it could be achieved, but it seemed that her skills in projections that she had developed in college weren't as rusty as she thought. They may be married on schedule after all.

"I'm telling you, I can get you and Sheldon some alone time." Penny winked at Amy, and Amy smiled back. She may just have to take her friend up on her offer this time.

The businessman tapped his empty glass on the bar to get Penny's attention and she walked away to refill his drink.

"So, Amy," Bernadette leaned in close. "Do you think Penny's been acting a bit strange lately?"

"How can you tell? She has always been the odd one in our group," Amy said.

Bernadette eyed her. "Really, Amy? _Penny_ is the odd one?"

"Well, she's the only one who isn't a scientist," Amy explained. "It makes sense."

Bernadette frowned, unconvinced. "Yeah… sure."

Their conversation ended as their friend sauntered back over to them.

"Anyway," Penny said, picking up the conversation where she left off, "Like I was saying, I'll see what I can do to get you and Sheldon some privacy. I have a few ideas."

"Thanks, bestie," Amy said.

* * *

Amy's nerves woke her up extra-early on Saturday morning.

She and Sheldon would be going on a double date with Ben and Claire that evening. Their plan was to eat at a local Japanese hibachi restaurant, and then they would attend Penny's play and - because Amy had promised - the after party as well.

The restaurant had been chosen by Amy. She'd never been to a hibachi restaurant, but had always wanted to go. They were always the most popular spots on prom night when she was in school. She could remember driving by the one in Glendale, and seeing all the girls' big, colorful, poufy dresses as they waited in groups next to their stretch limos, hanging on the arms of their boyfriends that looked like Ken dolls.

It had taken some convincing to get Sheldon to agree to it, but she was ultimately able to sway him by suggesting that if they sat around a grill, the opportunity for small talk would be greatly reduced.

Leonard was scheduled to drop Sheldon off at Amy's apartment at 5:00 p.m., and then they would meet Ben and Claire at the restaurant.

Amy rubbed her eyes and groggily looked at her clock.

_6:18 a.m._

She stretched her arms and pushed her feet out of bed. There was no way she'd be able to go back to sleep. She was too excited for everything that would be happening that evening. Instead, she began getting ready for the day.

She flossed and brushed her teeth, then tweezed her eyebrows. Finally, she turned on the shower and stripped down to her birthday suit, ready to hop in, but just as she slid the curtain back, she heard a familiar rapping on her door.

_Knock knock knock _

"Amy?"

_Knock knock knock _

"Amy?"

_Knock knock knock _

"Amy?"

_What is Sheldon doing here?_

She wrapped a towel around her body and quickly went to answer the door, glancing at the clock on her microwave along the way. She was glad Sheldon had fixed it for her. It had really proven to be handy.

The display indicated that it was only 7:00 a.m.

_Did we alter our schedule? I don't remember any changes…_

She popped open the door. There he stood, looking adorable in his light jacket and Flash t-shirt. He had a garment bag slung over his shoulder, and his satchel strapped across his chest.

His eyes grew wide when he saw her standing before him in nothing but a towel.

"_Amy_!"

"Sheldon, what are you doing here? It's seven in the morning."

"What are _you_ doing answering the door with no clothes on?!" Sheldon exclaimed. "What if I was a sexual deviant or criminal?"

Amy sighed. "I knew it was you, Sheldon. Your knock gives you away. You're not a criminal… and you are certainly no sexual deviant." She could stand for him to be a little more deviant in that area, if she was being completely honest.

"Still, one should not be answering one's door in a towel." Sheldon reprimanded.

"Again – I knew it was you. I wasn't worried." She opened the door wider, motioning for him to come in.

He stepped inside. "And you don't think it's inappropriate to answer the door naked, even if it is me?"

"No. Not if it is you," Amy said, matter-of-factly, closing the door behind him.

Sheldon looked horrified, but set his messenger bag down on the couch and held the garment bag between himself and Amy, using it to block his view of her scantily clad body. "Can I hang this in your closet?"

"Sure," she nodded.

"Thank you," he said, and began heading down the hallway to her bedroom.

"Wait… Sheldon?" Amy questioned. "Why are you here so early? I wasn't expecting you until this evening."

Her boyfriend froze in place and visibly stiffened.

"Umm…" he began. "I… uh… had to leave the apartment. I'm… uh… quarantining myself."

"What do you mean? For how long?"

"All day. I can't go back until this evening." He finally turned around to face her, but still avoided her eyes. Amy noticed that he was starting to twitch slightly – a dead giveaway that he was hiding something.

"Is the landlord spraying for termites or something?"

"No."

"Are you ill?"

"No."

"Is it Leonard?"

He nodded his head vigorously. "Yes. Yes, it is Leonard. I can't be around Leonard. Please don't ask me about it."

His twitching was becoming more prominent.

_Oh great._ The last thing she needed was to cause her boyfriend to malfunction.

"Ok, ok," Amy promised. "I won't. You're always welcome here. I just… I hope everything's okay."

"Everything's fine, thanks." With that, Sheldon turned and darted back to Amy's room to hang his garment bag in the closet.

"I'm going to take a shower," Amy called down the hallway. The hot water had been running this whole time, and the bathroom was quite steamy.

While she washed up, she wondered why her boyfriend was acting so strangely. _What could have happened between he and Leonard?_ She hoped it was nothing serious. It probably wasn't. Sheldon had said he would be able to return that evening, after all.

_Curious_, Amy thought, as she stepped out of the shower onto her floor mat.

_Maybe Leonard and Penny had requested some privacy before her performance tonight?_

She quickly towel-dried her hair and wrapped the towel around her body again. She hadn't brought clothes with her into the bathroom, as she hadn't planned on having company. Amy peeked out the door and heard the television in the living room, so she quietly tiptoed down the hallway to her bedroom and pulled on some comfortable clothes. She would just be hanging around the house until she had to get ready for their date that evening. There was no point in getting 'fancy' yet.

Amy grabbed her brush and began pulling it through her hair as she walked back into the living room.

Sheldon was seated on the couch, watching an episode of Star Trek on the SyFy Channel.

"So… are you going to be here all day?" she asked hopefully.

"Is that a problem?"

_Is that a problem? Of course it's not a problem! A whole day cooped up with my boyfriend all to myself? Heaven. Pure heaven._

Amy shrugged. "Nah. I don't mind."

"Thank you," he said.

Amy made some tea for the two of them and then sat down on the couch beside him.

"Do you want to do something?" she asked.

"Like what? A game?"

"There's that. Or…" Amy shrugged. "We could watch TV and… cuddle?"

Sheldon frowned at her.

"We've been over this, Amy," he said. "I love you, but there's no reason for us to be all squished together on this couch when there is plenty of room."

Amy sighed. His logic was sound. She was just happy to hear him say 'I love you' again.

"Counterfactuals it is, then," she smiled.

"Actually…" Sheldon leaned down and pulled a box out of his bag. "I thought we might play _this_."

He held the game out to Amy. It was a brand-new professionally printed version of _Research Lab_.

"Is this… what I think it is?" She asked.

Sheldon nodded. "The first one made. Your dad gave it to me. They aren't going to be officially printing them for a few more months, but they were testing things and … well… here it is. Hot of the press."

"Sheldon…" She took the game from him and ran her hands along the vacuum-sealed plastic. "You have no idea how proud I am of you."

Sheldon grinned broadly. "How does it feel to have a boyfriend who's not only a masterful scientist, but also a shrewd businessman?"

Amy giggled. "It feels great. Shall we play?"

Sheldon let Amy tear through the plastic, which he claimed was tantamount to him allowing her blow out his birthday candles.

They played for the better part of an hour. Amy won, of course, but Sheldon insisted that it was just a practice round and that they hadn't actually been keeping score.

After the game, they decided to watch a movie. Amy wanted to watch something romantic, but Sheldon insisted on watching Indiana Jones. They bickered for a few minutes, before Amy suggested a compromise.

"I'll watch Indiana Jones if we can cuddle." She crossed her arms over her chest and stared at him.

Sheldon narrowed his eyes at her and pursed his lips.

"Well?" Amy nudged.

"Do we have to cuddle during the _whole_ movie?"

"Yes."

"Counterproposal?"

Amy continued to glare, but motioned for him to offer his suggestion.

"We cuddle for 10 minutes," Sheldon offered. "And then we sit beside each other and hold hands."

Amy shook her head no, then made a counterproposal of her own. "We cuddle for _half_ of the movie, then we hold hands. When the movie is over, we kiss."

Sheldon gaped at her. "Now you're being ridiculous."

"Fine. We'll watch Twilight."

"Good Lord. Get over here." He held his arms open, so that Amy could cuddle up beside him.

Amy gave him a victorious smirk and crawled across the couch to lean into his side. It wasn't nearly as awkward as their first cuddle session had been. Amy wrapped her arm across his chest and he hugged her close to him.

The movie turned out to not be that bad after all… and it even had a bit of romance. Still, as time wore on, Amy's eyes grew heavy and she nearly fell asleep against him. She was startled awake when Sheldon shifted.

"The movie is about half over," he said.

"So?"

"Our agreement? We cuddle for half of the movie." He pulled his arms away from her and offered her his hand.

Amy frowned at it. _Oh, yeah._ She had completely forgotten about their agreement. She sighed and she placed her hand in his, settling back against the couch beside him. Then she smiled as she realized that the third part of their agreement was coming. The kiss.

When the movie was over, Sheldon moved to stand up.

"Do you want some more tea?" he asked, picking up their mugs from the coffee table. He was avoiding her eyes, and Amy knew he was hoping that the final stage of their arrangement might have slipped her mind.

_No such luck, Sheldon,_ she thought with a smile.

"_Excuse me?"_ Amy asked. "What about our kiss?"

His shoulders fell and he brought his eyes up to meet hers.

"Oh… right," he said. "I forgot."

She crossed her arms and gave him a disbelieving look. _Oh, sure. Like I'm supposed to believe that Sheldon Cooper forgot something._

He sat back down beside her. "Very well. Get on with it."

"Get on with it?"

"Yes." He leaned in to her, but didn't pucker his lips. He just sat there, waiting for Amy to plant a kiss on him.

_He looks so unhappy_, Amy thought. She couldn't kiss him like this. Not when she knew he would hate it so much. This wasn't like one of their spontaneous kisses in the past._ He knows it's coming this time, and its obviously torture for him._

So she surprised herself and did something she didn't want to do; She scooted away from him. She was going to let him out of the deal.

Amy stood up and grabbed his mug. "I'll make your tea."

"Wait…" Sheldon gave her a confused look. "What about the kiss?"

"That's okay," she smiled weakly at him. "We don't have to."

"Oh." He looked both relieved and hurt at the same time, so Amy didn't know whether she should be happy or disappointed by his reaction. She shrugged it off and wandered into the kitchen to brew the tea.

Around noon, Amy talked Sheldon into making lunch. He showed off his cooking skills by whipping up some Texas-style chicken-fried steak for Amy. He acted as chef, handling the bigger tasks, and directing Amy on the smaller ones. Between the two of them, the meal was finished in record time. Not to mention, the food was delicious.

However, the kitchen was left in a shambles, and Sheldon couldn't have that. As soon as lunch was over, the two of them tackled some serious scrubbing.

Amy's attempts at flirting during their kitchen cleanup not only were unsuccessful, they actually had the opposite effect. Amy coyly grazed Sheldon's arm as she leaned across to soak her sponge in the sink, but he jerked his hand away and scolded her for not maintaining the proper boundaries required for the chemicals in the cleaning supplies.

"But, Sheldon, we have gloves on," Amy said.

"And thank goodness for that!" Sheldon moved away from her and began filling the dishwasher with the rinsed pots and pans.

Amy didn't mind his reaction. She still liked the idea that they were doing such menial household tasks together.

_Look at us, it's like we're married! Doing chores!_ Amy smiled to herself, which earned her a perplexed look from Sheldon.

"Are these chemical fumes making you delirious or something?"

Amy bit her lip to keep her smiling at bay. "No. I'm fine."

Eventually, it was time for them to prepare for their date. Amy let Sheldon use her bedroom, while she went to change and get ready in the bathroom.

She decided to dress up a bit more than usual. She curled her hair slightly at the bottom, and pinned half of it back in a barrette. She didn't wear any makeup, but did opt for a little bit of tinted lip-gloss - even though she knew Sheldon wouldn't approve.

She pulled on her tights and her new knee-length, long-sleeved, loose fitting yellow dress. She slid her feet into the pair of heels that she had purchased when she went shoe shopping with Penny and Bernadette. She had never really had a chance to wear them, but tonight seemed appropriate. They matched her outfit well. Besides, Penny always told her to never let a good pair of shoes go to waste.

When she was done, she glanced into the living room to see if Sheldon was there. He wasn't.

_Must still be getting ready._

She wandered down the hall to her bedroom and knocked softly on the door.

"Sheldon?"

"Come in."

She nudged the door open and found Sheldon looking very dapper indeed standing in front of her full-length mirror in his dress clothes. He had on a pale blue shirt and a nice jacket. It appeared to be the same suit that he wore the day he was meant to accompany her to the funeral of a co-worker. The day he cared for her when she was sick. She'd always remember how he looked that day.

Amy leaned against the doorway, taking him in. _My sexy man_.

"I can't get my tie right," he groaned, wriggling it around on his neck in frustration.

She snickered to herself. "Here. Let me help you."

"Thank you," he sighed in relief, dropping his arms and turning to his girlfriend.

Amy took his tie in her hands and undid it. She straightened it on his neck and began flipping and tucking it through itself.

Her eyes occasionally darted up to his. He was looking at her, and she smiled bashfully.

"You're wearing lip gloss," he said with a hint of disapproval.

She nodded and finished the knot, slowly tightening it closer to his neck.

"You know I don't like that," he added.

She nodded and looked up at him, her hands still on his tie.

Sheldon reached his hand up to her face and began smudging her lips with his thumb.

The warmth of his finger on her mouth sent a shiver down Amy's spine. Her knees went weak and she thought she might collapse right there at his feet.

_If just one touch has this effect…_ Amy couldn't finish her own thought. It was too dirty for her to even think about.

Sheldon grimaced when he pulled his hand away and rubbed the stickiness of the gloss between his thumb and forefinger.

"Great. I need to wash my hands now."

That was all it took. Amy wasn't even sure what it was about his words that sent her over the edge, but she latched a death grip on Sheldon's tie and swiftly pulled him toward her lips.

Her mouth met his and Sheldon's eyes grew wide with surprise as she held his face to hers.

Eventually, Sheldon began to give in to the tight-lipped, close-mouthed kiss. Amy felt him relax into her and she closed her eyes, moving her hands from the tie up to his jaw, holding him gently in place.

After a few moments, she reluctantly ended the kiss, but continued to hold his face to hers, their foreheads resting against each other.

"What was that for?" he asked.

"Because I love you," Amy said. "I wanted to show you how much."

"Oh."

Amy noted a hint of confusion in her boyfriend's eyes. He looked as though he was thinking hard about something, or working out some complex equation in his head.

They stayed like that – their foreheads leaning against each other – for several more moments, until Amy began to pull away.

_He needs to finish getting ready_, she thought. _He'll be in a bad mood all night if I continue wasting his time like this._

But as she started to step back, she felt a weight against her hips and her breath caught.

_Is that…? Yup. Those are Sheldon's hands… on my hips. No big deal._

He gently pulled her back to him, their foreheads still together.

He held her in place for what seemed like an eternity, not saying a word.

_What is he doing?_ She thought. As much as she wanted to stand there in her boyfriend's arms forever, they really did need to get going. But just as she considered pulling away once again, she heard a quick intake of breath and Sheldon leaned forward, eyes closed, and pressed his lips gently to hers.

Amy melted into it. For the first time ever, Sheldon was kissing her.

_Forget dinner_, she thought. _Let's just stay in tonight. _Suddenly, she didn't care about the double date, Penny's play, or the fact that her family and all her friends would be waiting on them later that evening. She just wanted to perpetuate this moment.

She closed her eyes, and brought her arms up around his neck, pulling him closer.

His hands still hung loosely on her hips. Amy could tell that he was unsure what to do with them, or how long the kiss should last. She allowed herself a couple more heartbeats to burn into her memory the feeling, the sensation, the heat of his lips against hers, and then she pulled away.

They silently stared at each other for a moment, both in a state of shock at what had just happened.

"I still need to wash my hands," Sheldon finally said.

Amy frowned. _Way to kill the mood._

He pulled his hands off her hips and looked at the sticky remnants of Amy's lip-gloss still on his fingers. She stepped aside and let him leave the room, bound for the bathroom so he could clean up.

Once he disappeared into the hallway, Amy heaved a big sigh and touched her hands to her lips.

_This was already, without a doubt, the best night of her life._

* * *

**Chapter twenty-five coming soon!**

**Notes:** Please review! Constructive criticism is also very nice - I won't hate you if you don't like it! ;o)

I really appreciate ya'll. (I'm from Texas. Need I say more? lol)


	25. Chapter 25: The Double-Date Dissidence

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 25: The Double-Date Dissidence**

* * *

As expected, the restaurant was a hub of activity. It _was_ a Saturday night, after all.

Amy and Sheldon arrived just before the agreed upon time, but Ben and Claire weren't there yet. Since the couple couldn't be seated without their complete party, they waited on a bench next to a large fountain filled with coy fish.

Sheldon scrunched his nose at the murky water.

"Ick," he said. "The fish smell bad. And I don't think they clean this fountain regularly."

"Probably not," Amy agreed with a shrug. "But some bacteria in a pond like this can actually be beneficial for it's tiny ecosystem… even if it _is_ a little slimy." Some brownish sludge caught her eye. "Though, I think this one may be borderline unsafe."

She inched toward Sheldon to move away from a particularly suspicious looking bit of mossy goop that had accumulated on the edge of the pond near her. "It could probably be worse, though."

She set her hand on her boyfriend's knee, and instead of tensing or pulling away, he placed his hand over hers and smiled.

"No. I suppose it's tolerable."

_He's being surprisingly easygoing, _Amy thought.

Despite the fact that he was obligated to endure a double date, _and_ he was sitting mere inches from what could very easily be a mushy pile of disease-ridden marine plant life - with her hand on his knee, no less – he was unusually content. And Amy still couldn't believe that he had kissed her of his own volition less than an hour before. She debated whether or not to discuss with him the events that had taken place earlier that evening. _Surely he has questions… or concerns… or – God forbid- complaints?_

However, just as Amy had mustered up the courage to say something, a curly-haired blonde stepped through he doorway on the arm of a man Amy would recognize anywhere.

Ben was dressed to the nines, and had opted to get a haircut for the occasion, which Amy assumed was his girlfriend's doing.

"Hi Ben! Hi Claire!" Amy stood, dragging Sheldon up with her.

Ben gave an uncommitted wave, while Claire plastered a sincere smile across her face.

"Hello!" she beamed. "Its so nice to see Ben's friends again! I don't get to meet many of them, so this is a real treat for me."

"We aren't his friends," Sheldon said bluntly. He winced when Amy elbowed him in the ribcage.

"_I'm _a friend of Ben's," Amy said with a smile. "Sheldon here just met him the same day we met you."

"Oh I see," Claire said. "Well, I'm excited to be here with you all the same, Sheldon."

Amy nudged Sheldon again and he gave Claire an oversized, albeit slightly creepy, smile.

Ben had been silent the whole time, letting his girlfriend do all the talking. _I suppose that's how their relationship works_, Amy thought. _Ben's a pretty quiet guy, especially when you consider how bubbly Claire is. They balance each other well._

"I think we can be seated now. Is everyone ready to eat?" Amy asked.

They all nodded, and the hostess showed them to their seats. The group was placed around the hibachi grill, with either couple on the opposite side of a single corner. Amy took the chair closest to Ben at the edge, to spare Sheldon the discomfort of socialization.

Another family of four was seated at the table beside them. There was an average-looking middle-aged man and woman, a teenage boy dressed in gothic makeup and clothing, and a chubby little girl who looked to be no older than ten.

Amy smiled and waved at them. The little girl returned her wave with a cheerful grin. Amy noticed she was missing one of her front teeth.

Claire leaned forward so Amy and Sheldon could hear her over their tablemates' chatter and the clanging of metal cookware at a nearby grill. "So, Sheldon, what is it that you do? Where do you work?"

Sheldon threw Amy disapproving glance. It appeared the hibachi table setting would not allow him to escape the small talk, as Amy had led him to believe.

"I'm a theoretical physicist," he answered. "I work at Caltech."

"How about you, Amy?" she asked.

"I work at UCLA. I'm a neurobiologist."

"Oh wow! Two science-types! Just like my Ben here!" She smiled and patted his hand.

Ben frowned at her touch, but didn't pull away. He looked at Amy to see if she had acknowledged his progress, and she rewarded him with a sideways smile. _He is making allowances for Claire._ She remembered the time that Ben had pulled away from her in the deli. With Claire it was different, though. She was special. Her touch meant something more to him. Amy received similar treatment from Sheldon. He had made so many concessions for her; She was able to touch him, hug him and now, it seemed, even _kiss_ him with limited resistance.

_Sheldon and I are unique… but we aren't alone. _She smiled at the thought.

The chef came out to take their orders, and then quickly hustled back to the kitchen, promising to return shortly.

"So, Claire," Amy said, eager to keep the conversation lively. "I know Ben is a chemist. What is it that you do?"

"I'm a school teacher. Second grade," she shrugged. "Not so amazing as what you all do, I know."

"Not true." Ben spoke his first words since the group had arrived. He'd been so quiet that Amy almost forgot he could talk.

"Without people like you shaping the minds of young children," Ben continued, "today's Nobel prize winners might never have achieved such success. Who knows which advancements the world would be deprived of today if grade school teachers didn't exist."

Amy was surprised with how succinctly Ben had delivered such an impressive complement to his girlfriend… and Claire looked like she could just about cry.

Ben gaped at her with a slightly panicked look in his eyes. "I didn't mean to upset you!"

The blonde shook her head and used a finger to blot under her eye, so that a tear wouldn't fall.

"It's a girl thing," Amy whispered to Ben. "Don't worry. She's not upset." Amy was proud of herself. A few years ago, she would have been just as confused by Claire's emotional response as Ben. Amy realized her mother had been right after all. _I've grown so much._

"Oh, I see." Ben still looked confused and uncomfortable. So, despite his aversion to talking to new people, he diverted his attention to Sheldon in order to avoid any further unease with Claire.

"So, Sheldon," Ben said. "Theoretical physics, eh?"

"Yes." Sheldon frowned again at Amy.

_I know, I know,_ she thought to herself. _I promised him limited interaction. I suppose I'll have to be punished later. _A sly smirk formed on her face.

"Any great breakthroughs I should know about?" Ben asked.

"I'm always working on a great breakthrough. That's what makes physics the most important of the sciences. There's the potential in every day for my mind to birth a life-changing discovery. My brain is truly the womb of exploration."

_The 'womb of exploration'. _Sometimes Amy forgot how poetic her boyfriend could be._ Be still, my heart._

Amy's loins may have been set afire, but Ben seemed shocked by the Sheldon's premise and shook his head in offense. "_Excuse me?_ How is physics any more important than chemistry?"

Amy hung her head. _Crap._ She was afraid this might happen. When two hardheaded scientists like Ben and Sheldon get together, it can cause trouble. A similar disagreement almost caused a permanent rift between Sheldon and herself so many years ago.

"Physics is the science of _everything_," Sheldon explained. "And as such, any great breakthrough in physics can be applied to all other scientific fields."

"There would be no physics without chemistry," Ben argued.

"No," Sheldon said firmly. "There would be no chemistry without physics."

"You, sir, are mistaken." Ben leaned forward across Amy to continue the debate, but the chef wheeled in a cart with their food, and the moment was interrupted.

_Thank God_, Amy said to herself.

The chef squeezed some sort of liquid – she assumed a type of alcohol - across the heated grill and lit it on fire. The flame shot across the table and a wave of heat washed over them.

The little girl in the family beside them squealed and clapped her hands in delight.

"Chemistry." Ben pointed to the grill. "_That's_ Chemistry."

Sheldon rolled his eyes. "Of course it is. It's all nonsense and theatrics. Physics is beautiful in its vast, subatomic complexity. It's not dependent on explosions and other such piffle to keep people interested."

It was Ben's turn to scoff. "_Doesn't depend on theatrics?_ What do you call black holes and supernovas? Or even multiple dimensions and wormholes? Theoretical physicists have been dreaming up the most over-the-top and bizarre objects in the universe for _years_. _Parallel universes? _Come on…"

"Ha! Shows what you know. We _discover_ these objects. We don't _create_ them. We are merely pointing out things that actually exist in nature… or that _may_ exist in nature," Sheldon said. "We don't create pyrotechnical displays just to show off at concerts and fireworks shows."

"The world is filled with chemical reactions! It's not all fire and explosions! These reactions allow scientists to…"

Amy was only half-listening to the boys' verbal scuffle. She had her eyes on the chef; entranced by the way he moved his hands and tossed the knife around his fingers with ease. Even Sheldon forced himself to stop his bickering when the man make a cone-shaped train out of stacked onion slices. Her boyfriend 'choo-choo'ed along with the chef as it was nudged along the grill, steam pouring out the top.

In that moment, Amy was pleased that Sheldon was able to find a way to enjoy himself, but, to her dismay, it was short-lived. As soon as the onion-train spectacle was over, he returned his attention to the argument at hand.

When Sheldon complained that chemistry is no more than applied physics, Ben rebutted with a jab at the 'unproven' nature of theoretical sciences. Sheldon returned fire by hurling an insult at Ben about how his workplace most likely reeked of 'nose-hair singeing' hydrogen sulfide.

"There are chemical reactions going on _every_ day inside the human body," Ben defended, ignoring the insult about his workplace. "Without having studied these reactions, we'd have no idea how the basic functions of life work."

"Well, consider this," Sheldon countered. "Astro-_physicists_ discovered that the most basic parts of the human body have been found to have the same material as the stars. The STARS, sir! These are the _same_ elements that were formed in the creation of the universe… and as physicists are the ones looking at theories for the universe's conception, by default this would mean that physics predates chemistry."

"So you _claim_," Ben rolled his eyes. "Sure, people may be made of some celestial materials… but you can't _prove_ those specific elements _came_ from the stars. You're guessing. Bottom line: Chemistry can be proven. It produces testable results. What are you working on? String Theory? I _dare_ you to provide me with one _iota_ of proof that String Theory is the be-all-end-all of a grand unifying theory. I'm not saying you're wrong… but I'm challenging you to prove that you're right."

Sheldon began to twitch in anger. "Of all the nefarious, vile – "

"Gentlemen!" Claire called out with a raised voice. "Both chemistry and physics are important! Can't we all just get along, here? You're acting like my second graders."

The boys stopped their quarrel, both breathing hard and fuming. They stared at Claire for a moment after her outburst and then turned to Amy.

"What do you think, Amy?" Ben asked. "You're a scientist. Which field is more beneficial?"

Amy glanced back and forth between the two men. She was the meat in an egotistical sandwich.

"I agree with Claire. Both fields have their merits."

"Hey! I'm your boyfriend! You have to agree with _me_!" Sheldon whined.

"Says who?"

"Says YOU," Sheldon answered, pointing a boney finger at her. "You made me side with _you_ over Wil Wheaton… and he was on Star Trek! This fellow is just a mediocre chemist." He waved his hand derisively at Ben.

"Who are you calling _mediocre_?" Ben asked. He started to rise out of his chair, but Claire grabbed is arm and whispered something in his ear, which seemed to calm him down.

"Sheldon, Wil Wheaton was being _unreasonable_," Amy argued. "The situations are nothing alike." _Wil Wheaton is a horrible actor and an incredibly rude human being_, Amy thought. She couldn't see why Sheldon liked him so much.

A cheer from the family beside them got their attention. The chef had just tossed a shrimp into the little girl's mouth. She was bouncing up and down in her seat, excited.

Amy frowned. _Dang. I missed the shrimp toss. I wanted that. _She had heard about such activities taking place at these establishments and had very much wanted to participate.

"The point is," she continued, pushing through her disappointment, "We are here to spend a pleasant evening with each other. Please don't ruin it for Claire and I, or you'll have to deal with our wrath later."

The men quieted down and settled back in their chairs.

Sheldon immediately fumbled for Amy's hand under the table. He found it, and squeezed it tightly.

Ben eagerly studied their clasped hands, then reached out and took Claire's palm in his, holding it loosely in her lap. Amy could tell the gesture took Claire completely by surprise. She gaped at Ben's hand on hers.

Ben threw a timid glance back at Amy, and she gave him a reassuring nod of approval. He was learning. _At this rate, they'll move along at triple the speed that Sheldon and I have been going._

"So Amy, how did you and Ben meet?" Claire asked, in a desperate attempt at more friendly conversation. "Ben here has been annoyingly vague on the matter."

Amy eyed Ben carefully. She hadn't told Sheldon about Ben's role in the removal from her project at work, and didn't really want to cause any more trouble between the two of them.

"Umm… we… worked together," Amy said. _Not untrue._

The chef began scooping fried rice onto their plates, and Amy immediately picked up her fork and started shoveling it into her mouth.

"Worked together?" Claire furrowed her eyebrows in confusion. "But you work at different universities. What did you do together?"

At this, Sheldon also perked up. "I must admit, I don't see any logical reason that the two of you would be working together, either. Amy, you haven't mentioned any new projects. As far as I know, you've just been picking at your brain samples like a leftover holiday ham. Day in and day out… brains, brains, brains."

Amy had never been very good at coming up with lies on the fly.

She and Ben looked at each other. "Umm…"

"I worked with Amy on an analysis of brainwave stimulants at her laboratory. I was a participant in one of her studies."

"Oh, ok," Claire nodded. "The one you were kicked out of for some inexplicable reason?"

Ben nodded and shifted his eyes back to Amy. They both repositioned themselves uncomfortably in their chairs.

"That's funny… Amy was removed from that project as well," Sheldon said.

"Mmhm." Amy nodded, and pushed another forkful of rice into her mouth. The chef was now passing around sautéed vegetables.

"Amy, you never told me why you were removed," her boyfriend continued.

"No. I didn't." She filled her mouth with veggies. "These are good. You should eat some."

"Why were you removed?"

"Mmmm… I'm not kidding. These are really tasty. Claire? Have you tried the squash?"

Claire looked from Amy to Ben, curiously. "This has something to do with Ben, doesn't it?"

_Dang, she's a regular gumshoe, isn't she?_

Amy stopped chewing at looked at Ben._ There's no way I can keep this up. I'm awful at this kind of stuff. _She swallowed her food and sighed.

"Fine…"

"Amy!" Ben sat up straight in his seat.

"Ben, They're going to find out. I'm a horrible liar."

"I thought you were doing fine."

"Well, you could have chimed in to help."

"I'm a bad liar, too."

"Couldn't be any worse than – "

"Helloooo?" Claire interrupted. "What happened? Why were you two removed from the study?"

Ben and Amy looked at each other again, and Amy motioned for him to explain.

"Because we were caught together outside of the university," Ben said matter-of-factly.

"Well, you could have said it in a way that didn't sound so scandalous," Amy rolled her eyes.

"Scandalous? What would have been scandalous about…" A look of realization came over Claire's face and she stood up, throwing her napkin down on the table. "What do you mean you two were 'caught together'? Were you 'seeing' each other? Was it a date?"

"A date?" Sheldon rose out of his chair, too. "Amy, is this true? If so, this is a blatant violation of – "

"No!" Amy said. "Well… I mean, yes we saw each other outside of the study, but no! It wasn't a date. We've always just been friends. Only friends. I love _you_, Sheldon."

A momentary look of relief came over Sheldon's face, but it was quickly replaced by a scowl.

"And you risked advancing at work for a friendship with… _him_?" Sheldon motioned toward Ben with disgust.

"Hey!" Ben's voice was elevated again and he jumped out of his chair to be on Sheldon's level. His eyes were throwing daggers in the physicist's direction. "I already feel bad enough about that whole ordeal. No need to pick at the wound."

"Ben, it wasn't your fault," Amy reasoned. "You shouldn't blame yourself."

"What do you mean it isn't his fault?" Sheldon argued. "Of course it is!"

"Sheldon!" Amy rose and stood defensively in front of Ben. Both couples were now on their feet and fuming.

"Excuse me?" The meek voice of the man in the family next to them broke through their argument.

"_WHAT_?!" All four of them yelled back at the man.

The whole family was staring at them with open mouths and wide-eyes.

"We're trying to have a nice dinner over here," the man said. "It's my daughter's birthday, you see."

They all looked at the girl and then slowly sat back down in their chairs.

"Sorry," Claire muttered.

"Happy Birthday," Amy added under her breath.

The rest of the dinner was awkwardly hushed. The boys remained quiet, but shot occasional glares at each other across the table.

A few times, Amy and Claire tried, unsuccessfully, to start up a new conversation. They would open their mouths to say something, but no sound ever escaped their lips. Each time, they would instead fill their wordless mouths with a spoonful of chicken or beef.

Toward the end of the meal, Ben finally broke the group's silence and asked Sheldon to pass him the soy sauce. In a truly child-like manner, Sheldon purposely tossed the bottle just out of his reach. The glass cracked on the table in front of Amy, sending sauce splattering across her lap and onto her yellow dress.

"Dang it!" she cried, as she tried to wipe the sauce away with a moist napkin, to no avail.

Sheldon apologized profusely, insisting she hadn't been his intended target.

"Why did you even throw it, Sheldon?" She asked angrily. "You could just as easily have acted like an adult and placed the bottle in Ben's hand."

"Here, let me help you…" He grabbed another napkin off the table and began patting it on her soy sauce covered lap.

Amy immediately tensed at her boyfriend's touch. He was rubbing her thigh dangerously close to her… um… lady parts. Her face reddened as Sheldon continued to dab at the spot near her crotch. He seemed oblivious to the effect it was having on his girlfriend.

After a few moments, Sheldon got a little too close for comfort in a public setting. As a reflex Amy snapped her legs together, and Sheldon froze. The reality of what he was doing - and where his hands were – had finally set in. He clinched the napkin in his fist, slowly pulling away and looking down at his dinner plate. His face was just as red as Amy's.

"I'm going to have to go to the restroom and clean up." Amy managed to squeak out. Sheldon nodded, but avoided her gaze.

She stood up, and Claire followed suit. "I'll come with you," she said.

_Ooo – A group visit to the little girl's room! This must mean that Claire wants to be friends._

She faltered briefly, realizing that this meant the boys would be left at the table alone, but the hesitation quickly passed. _They need to get over it_, she thought. Besides, she decided that she could use a few minutes away from Sheldon to get control over her… flustered state.

Amy smiled at Claire. "Sure, lets go." She turned to Sheldon and placed a hand on his shoulder. "I'll be right back."

He nodded quickly, but didn't make eye contact.

Amy and Claire left the table, making a beeline for the restroom.

"I'm sorry for the way I behaved earlier," Claire said as the girls crossed the restaurant. "I shouldn't have accused you of… you know."

"No need to apologize. It's the boys who are being ridiculous."

"They really are, aren't they?" she laughed.

Once in the restroom, the girls went to work on Amy's dress. Claire lathered hot water and soap on a paper towel, and rubbed it on the stain. Thankfully, Amy had brought a stain remover pen with her. She used it to blot at the little brown patch, but wasn't having much success. The stain was lightening, but wasn't completely going away.

Eventually, the girls decided they had done all they could, and Amy began drying the now wet spot.

"Great. It looks like I peed myself. It's like a flash back to my school days," Amy sighed, and Claire giggled.

"Nothing I'm not used to with my elementary school kids."

_Elementary school? Try middle school._ Amy could vividly remember wetting herself in eighth grade after head cheerleader Mandy Watkins lunged at her from behind, literally scaring the pee out of her. Of course, in her startled state, she'd also dislocated Mandy's shoulder with a swift, but effective spin and arm thrust. It hadn't made the moment any less embarrassing, though.

"Don't worry. It'll dry." Claire smiled at her and Amy couldn't help but feel better. She was very easy to get along with; Amy could see why Ben liked her so much.

"You'd make a good teacher, you know." The blonde pulled another paper towel out of the dispenser and handed it to Amy.

"What do you mean?" She couldn't see herself teaching children. _Dealing with snotty noses and sticky hands all day? No thank you._

"I just mean… you've obviously taught Ben quite a bit," Claire crossed her arms over her chest and leaned against the counter.

Amy grabbed another paper towel and began drying her hands. Had Ben told her about their relationship discussions? That didn't seem like something he would do.

Claire smiled slyly at Amy's confusion.

"I'm more observant than Ben thinks I am," she explained. "I'm an educator. I can tell a student-teacher relationship when I see one."

Amy blushed.

"I've noticed the way he keeps looking to you for direction," Claire continued. "In just a few weeks we've gone from being 'just friends' to dating… and now even hand-holding. I figured it would take me at least another year of working on him to get here."

"Umm…" Amy didn't know what to say. She didn't want to give Ben away, but Claire was quite the little detective.

"Don't worry," Claire assured her. "I'm not telling Ben what I know. You think I'm crazy? I'm loving this. You're good. I owe you a thank you."

"You're welcome." It was the only response she could think of without divulging everything that she and Ben had talked about.

"I only hope to one day be where you and Sheldon are."

Amy laughed out loud. "Where _we_ are? We aren't much further along than you two. You'll probably pass us up before long."

"No, I've seen the way he stares at you when you aren't looking. That's pure passion."

_Pure passion? Sheldon?_ Amy couldn't deny that she had felt it before. She often involuntarily shuddered with excitement when her boyfriend gave her 'that look'. It made her all tingly in … places. But she didn't think that outsiders had been picking up on it. Heck, she wasn't even sure Sheldon was picking up on it.

Still, after all these years comparing her dating life to that of her friends', it felt good to finally be in a relationship that another couple was striving to emulate. It was flattering, to say the least.

Feeling a little more confident, Amy decided she was ready to rejoin the men.

The girls returned to the table to find Sheldon and Ben sitting in silence, red-faced and arms crossed, looking away from each other like toddlers in time out.

"Are you two still upset?" Claire asked. "Amy's the one who should be angry. It's _her_ dress you ruined."

Sheldon looked at the stain on Amy's dress and uncrossed his arms. His expression softened to one of guilt. _Or maybe that's embarrassment from accidentally groping me earlier?_ Amy wasn't sure.

"We've apologized to each other," he said. "Doesn't mean we see eye to eye, though."

"Certainly not," Ben added. "But... we _have_ agreed that, at least for the rest of the night, we will be civil."

"Well… that's progress, I guess," Amy said. She noticed that while she and Claire had been away from the table, the boys had paid for the food. _How nice of Sheldon_, Amy thought. He usually would ask her to chip in. _He must really be feeling guilty._

She turned to Ben and Claire. "Would you like to ride with us to the play? There is an after party later that you are also invited to attend."

The couple looked at each other. Claire batted her pleading eyes at him and Ben groaned, but nodded. "I suppose that would be okay."

Claire winked at Amy behind Ben's back.

The group collected their belongings and left the table, migrating to Amy's car in the parking lot.

As they crossed the pavement, Amy analyzed what had transpired during their tumultuous dinner. She couldn't believe how childish Sheldon had been. Sure, she had expected _some_ resistance as a result of the forced small talk, but he'd blown it completely out of proportion.

The day had started out so well, and she'd had such high hopes for the evening. It was an opportunity to develop a relationship with another couple so similar to them. Sheldon _had_ to understand that his behavior wasn't okay. Just thinking about how he'd acted made the anger bubble up inside of her again.

Sheldon chose the wrong moment to try to grab Amy's hand. He reached for her and she immediately pulled away. She glared at his stunned expression.

_He can't honestly think that I'm over this. He insulted my friend and ruined my dress._

But, as much as she wanted to be _that_ woman – the one who was able to lay down the law with her man – she knew that her anger wouldn't last. Despite Sheldon's juvenile behavior, the evening had also shown him to be the most… manly… he'd ever been in his life.

She shuddered excitedly as she recalled the way he had been so forceful with her in the bedroom. She snickered at her own thought. _'Forceful in the bedroom'… Sheldon._ Two things she never thought would be said in the same sentence.

She knew that Penny or Bernadette wouldn't necessarily classify his bedroom behavior as 'forceful', but, to Amy, that was the most commanding romantic action Sheldon had ever been brave enough to undertake. He'd taken control, and she loved it.

Not to mention, at dinner he had almost skipped second base and moved right on to third without even realizing it.

_This evening has been such a rollercoaster. It's exhausting._

She sighed as she unlocked the car and the four of them piled in.

* * *

**Chapter twenty-six coming soon!**

**Notes:** I love me some reviews. If you'd leave one, I'd be much obliged to ya. ;o)

And sorry for the delay on this one. I just wasn't happy with it for the longest time. It took several re-writes/edits for me to be pleased enough to publish it. I've literally reviewed and edited it EVERY. SINGLE. DAY.

I know, I know… I'm too picky. Lol


	26. Chapter 26: The Overture Expiation

**NOTE: **I usually make my notes at the end of my chapters, but I feel I owe you all a pre-chapter note this time. I am really sorry for the horrendous gap in time between this chapter and my previous one.

I had an emergency situation, and it left me unable to write for a few weeks. Had I known about it before I posted my last chapter, I would have given you some warning.

Sincerest of apologies. (_Now that I think of it... I guess my chapter title kind of has a double meaning, eh?)_

* * *

***The Compatibility Constant*  
Chapter 26: The Overture Expiation**

* * *

Amy, Sheldon, Ben and Claire arrived at the theater to find Leonard shooting the breeze with Penny's father on the steps outside.

A rotund blonde woman stood a few feet away from them. Her eyes gave her identity away, but - aside from her golden hair, which Amy assumed was originally a more 'dishwater blonde' color - nothing else in the woman's physique hinted at the fact that she was Penny's mother. The woman's deep purple gown was about two sizes too small, but her hair was done up nicely. Penny's handiwork, Amy assumed.

Leonard looked nice, too. Even better than the night that he'd agreed to be her date to UCLA's 'wedding of the season'. She watched him run a hand through his well-coiffed hair as he spoke to Penny's father with ease. Amy had always admired how well those two got along, and she had been happy to discover that it was the same way with her own boyfriend and father.

As she watched him, Amy remembered the reason that Sheldon had been forced to spend the day at her apartment. It was something to do with Leonard. Was he ill? She hurried to hug him.

"Hello Leonard. Is everything okay?"

Leonard gave her a befuddled expression, but accepted her hug. "Sure. Why wouldn't it be?"

"Well, Sheldon said – "

"Amy!" Sheldon interrupted his girlfriend loudly, and pointed to some obscure thing in the distance. She squinted in the direction he was indicating, but saw nothing of importance. Amy turned back to him with a questioning expression plastered on her face. _What is his problem?_

Sheldon stuttered a moment before continuing. "I … I thought I saw your parents. We should probably go find them. I'll bet they are looking for us."

"They'll find us, I'm sure," Amy said, returning her attention to Leonard.

She'd been anxious to meet Penny's parents. _I'm sure they're just as excited to meet their daughter's best friend,_ Amy thought. _They've probably heard all about me._ But before she could speak to them, Sheldon grabbed her hand and pulled her away.

"Let's look for them, Amy," he said eagerly.

"Bye, guys," Leonard waved at them, and he and Penny's father shrugged at each other.

Amy groaned as she was tugged along. "_Okay_, Sheldon… I'm coming. Let go, please. You're hurting me."

Sheldon quickly dropped her arm. "Sorry."

She rolled her eyes at him. _Why is he acting so strangely?_

"It's fine," she said, massaging her shoulder, but then glanced back and sighed. "Sheldon… we've lost Ben and Claire." She found that it was becoming more and more difficult to hide the frustration in her voice.

Sheldon looked around and a smile formed on his face. "So we have."

"You were _wanting_ to lose them, weren't you?" She threw him a disgusted glare.

"It wasn't my goal, but I won't lie… it is a happy side effect."

"You're unbelievable."

"I don't know what you're upset about. Usually, you look for any excuse to be alone with me."

Something about his self-satisfied smirk made her want to slap it off of his face.

"If you had pulled me away from them solely for the purpose of being alone with me, then you're right; I would not be upset. But you and I _both_ know that's not the case. You're just being… _you_."

Amy was shocked by the harshness in her own voice. Her boyfriend's smug expression faded, replaced by one of confused guilt. He'd done something wrong, and he knew it, but she could tell he wasn't entirely sure what it was.

Amy sighed once again. "Let's just look for my parents, I guess."

The couple searched through the throngs of people. Her parents had agreed to meet them on the stairs, but the front of the theater was too large and crowded for them to easily find each other. Amy knew that Sheldon would soon start to panic, as the number of people was way over his "trample limit" of thirty-six.

As the minutes wore on, more and more people congregated around the white marble stairs, awaiting the opening of the large grand doors that would lead into the auditorium. And sure enough, as the two of them became encompassed by increasing amounts of warm bodies, Sheldon began to have his inevitable meltdown.

"Oh sure, '_give me your huddled masses'_," Sheldon shouted to nobody in particular. "How's that working out for you, Lady Liberty?"

Several nearby people glowered in his direction.

"Well I, for one, am happy to see such a great turnout," Amy argued, following a few paces behind her boyfriend. "It bodes well for Penny's prospects."

Sheldon huffed.

"What's wrong, Sheldon? You've been in a foul mood since the start of dinner."

They stopped walking and Amy leaned against a decorative pillar, giving up on their quest to find her parents and secretly cursing her decision to wear her yellow heels. A large, ornate lion stood atop the column, hovering over them like the darkness forming in the clouds above. She hadn't noticed that raincloud before. _I hope they let us in soon. _

"I'm fine," Sheldon shrugged and crossed his arms. "Why would you think otherwise?"

"Oh, _I don't know_," Amy rolled her eyes sarcastically. "Maybe your ridiculous behavior at the restaurant, the fact that you are acting strangely around Leonard, and now you're yelling at the Statue of Liberty… which is more than twenty-seven hundred miles away. And inanimate, I might add."

Before Sheldon could respond, the theater employees pushed open the large front doors and the crowd surged forward. In the commotion, a burly, tattooed man who looked awkward in his formal suit managed to bump into Sheldon, sending him abruptly in Amy's direction. The two crashed into each other, and Amy slammed into the pillar behind her.

Sheldon quickly pushed himself away from his girlfriend and scowled at the gentleman who hadn't so much as given them an apologetic glance.

"The nerve!" His face reddened with anger. "Some people have absolutely no idea how to function properly in society."

Amy couldn't help but laugh. _He's one to talk._

She was about to tell him as much, but a twinge of pain coursed through the back of her head, and she impulsively brought a hand up to find the source of the injury.

"Ouch!"

"What's wrong?"

"I must've hit my head," She gently touched her palm on the sore spot. _Just a little tender. Nothing too bad._

"Do you need something? Ice? An ambulance?"

"No, I'm fine. It just smarts a bit."

"Let me see it…"

"Honestly, Sheldon. I'm fine."

"Relationship agreement. Boo-Boos and ouchies. This is non-optional." Sheldon gently fought with her, batting her hands away, until she gave in and turned around so that he could inspect her scalp.

"See, I told you. It's fine," she said before he'd even had a chance to look at it.

That was how her parents found them - Sheldon digging through her hair like a chimp.

"Here you two are." Her mom pushed her dad along in his wheelchair. _No wonder they hadn't found us before_, Amy thought. _It was probably hard for them to navigate through the crowds with such a large piece of equipment._

Sheldon was too engrossed in taking care of Amy to notice her parents' arrival.

"Yes. It appears to be okay." He gave her head a gentle kiss where she'd hit it, then smoothed out her hair and stepped away.

She touched the spot again - this time more out of confused shock, rather than pain. "What was _that_ for?"

"My Meemaw always gave me kisses on my minor bumps and bruises when I was younger. She said it made them heal faster. I never understood _how_, considering the fact that the action leaves behind untold germs from the kisser onto the kissee. It's always worked, though. And if science has taught us anything, it's that if a theory has proven successful thus far… why change it?"

Even though it made absolutely no scientific sense, Amy noticed that the pain actually _did_ die down a little. _Interesting_.

Sheldon jumped when he finally noticed Carol and James. Amy's mom was smiling warmly at the two of them, watching their interaction. Meanwhile, James looked incredibly uncomfortable fidgeting in his chair with his cast-covered leg sticking out straight. Amy was about to ask how they'd managed to get the wheelchair back down the stairs of the apartment building, but Sheldon got to him first.

"We played the game!" her boyfriend said, excitedly.

"Well, hello to you too, Sheldon," James said with thinly veiled sarcasm.

"I'm sorry. '_Hello'_," Sheldon returned. "We played the game!"

"That's great," James laughed. "How was it?"

"Honestly, I considered keeping the first printed version of _Research Lab_ unopened, because who knows how valuable a mint in box version might be someday," Sheldon said. "But your daughter insisted we play."

"Hey! I did no such thing!" Amy crossed her arms over her chest. "It was you who wanted to play!"

Sheldon waved her off and launched into a discussion with James about the details of game, taking control of the wheelchair from Carol without even asking. The men wandered off, Sheldon pushing James up the wheelchair ramp, still engrossed in conversation.

Amy rolled her eyes and turned back to her mother, only to discover Ben and Claire standing next to her.

"Sorry we kind of left you alone back there," Amy said. "That was unintentional."

Ben seemed annoyed, but Claire brushed off Amy's apology with a wave.

"No problem! We got to meet your friend Leonard," the blonde said with a smile. "He's a bit unusual, isn't he?"

Amy nodded at Claire; _Leonard really is quite the odd duck._

She took advantage of the Sheldon-free moment to introduce her new friends to her mother.

Claire greeted Carol with a friendly smile, but Ben was distracted - his eyes darting about, taking in his surroundings. His girlfriend gave him a gentle nudge, which he didn't seem to notice.

"There are too many cracks in these stairs," he muttered, studying the intricately laid mosaic marble patterns leading the way into the theater. Amy recalled how Ben had been careful to navigate his way around the grout lines of the tiled hallway outside of her office. _This must be torture for him_, she thought, feeling a bit of pity for the obsessive-compulsive man.

Without batting an eye, Claire took his arm and spoke something quietly to him. Amy noticed her pointing out a pathway up the wheelchair ramp, which avoided the staircase and had significantly fewer cracks.

Ben smiled and nodded.

Carol assessed the couple with a raised eyebrow, before leaning in to whisper in her daughter's ear. _"And I thought you and Sheldon were unusual…"_

Amy smiled at her mom and started to say something about how every couple has its quirks, but was distracted by someone else calling her name. She spun around to find the source of the voice.

She gasped when she saw her red-headed co-worker stepping toward her.

"Hannah! What are you doing here?"

"Well, you mentioned your friend was performing, and I thought I'd do the good friendly thing and stop on by to show my support," Hannah said. "Also – and more importantly - I have no life. So, seeing as I had nothing better to do tonight, I figured that I may as well be social." She laughed and gave Amy a hug.

If Hannah hadn't approached her, Amy probably would not have recognized her. She'd never seen Hannah without her lab coat. She was wearing a tight black dress and her hair was slicked back into a bun. Instead of her typical vibrant-colored spectacles, she had on a classic black-rimmed pair. She looked like a completely different person.

"I'm glad you're here! You remember Ben," Amy said, re-introducing them.

"Oh! Yes, Hello," Hannah reached her hand out to him, but he instead reached over and grabbed Claire's hand, leaving Hannah's hanging awkwardly in mid-air.

"And this is his _girlfriend_… Claire." Amy gave Hannah a look, to make sure her friend had acknowledged the emphasis she'd placed on the word '_girlfriend'_. She didn't need any of Hannah's jokes tonight in front of Ben, Claire or Sheldon. Especially not after what had happened at dinner that evening.

Hannah gave her an understanding wink, and Claire took Hannah's proffered hand, which had been jilted by Ben.

After introducing her friend to her mother, everyone began filing into the theater, as the play was about to begin.

"Have you guys seen Bernadette and Howard?" Leonard asked as he trotted over to them.

Amy and Carol shook their heads.

"And what about Raj?" Amy asked.

"I assume they are all coming together, but I haven't heard from them."

The three of them made a cursory glance through the dispersing crowds, but saw no signs of their tardy friends. Eventually, they shrugged and followed the droves of people still filing into the auditorium, deciding that the trio would find them once they arrived.

* * *

The majority of the seats in the first two rows had been reserved for Penny's group.

Amy offered her father's reserved seat to Hannah, since James was planning to remain in his wheelchair in the aisle throughout the production.

"It'd be less of a spectacle than me trying to maneuver my way into another chair," he reasoned. Hannah graciously accepted, and took a seat in the second row – where Bernadette, Howard and Raj would also sit… if they ever showed up.

"I don't know how I feel being on the front row," Sheldon said as he sat down between Leonard and Amy.

Leonard groaned. "What's wrong with the front row?"

"Well, I don't know if I like the idea of sitting so close to the actors. I don't want to the be target of stray spit."

"Don't be ridiculous. You'll be fine."

"To be honest, I feel a bit awkward being on the front row, too," Amy said.

Ben nodded in agreement. "It's very… open... isn't it?" He glanced around at the people passing to and fro in front of them, scouring the auditorium for their own seats.

"You know, in many churches they have what's called a 'modesty rail'," Sheldon explained. "Its essentially just a wooden construction which has a sole purpose of keeping prying eyes from ogling up the skirts of the women on the front row or in the choir area. Though, if reverends' are _that_ concerned about their congregation's lustful eyes wandering up ladies' skirts… they aren't really doing a good enough job keeping their flock on the moral high ground, now are they?"

He did a double-take at Leonard's gaping expression.

"What?" Sheldon asked his confused friend.

"How is that information useful?" Leonard's brow was creased with frustration.

"I didn't say it was useful. It's merely relevant."

The bespectacled man rubbed his temple, and peered at his roommate. "Well, we don't have a modesty rail here. So, what do you want us to do?"

"I suggest we move to the second row."

"We aren't moving. Penny reserved these tickets for us, and she will be expecting to see us on the front row."

"We also have several seats on the second row reserved. Once Koothrapali, Bernadette and Howard get here, they can have our seats on the front row."

Leonard stared at him in bemused shock. 'You do what you want. Penny's parents and I are staying here."

"Fine. _We'll_ move. You can enjoy the plethora of spittle missiles from the players as they effort to project their P's and T's across this large auditorium."

"Fine."

Sheldon, Amy, Claire and Ben rose and made their way to the aisle.

"Do you think they have Cracker Jacks?" Sheldon asked as he slid into the second row next to Amy.

"Why would you want Cracker Jacks?" Leonard turned around in his seat to face his roommate, the stress of having to continually apologize to Penny's parents for Sheldon's behavior was evident on his face.

"Why _wouldn't_ I want Cracker Jacks, Leonard? Cracker Jacks are delightful. It's popcorn with caramel and peanuts. And there's a prize at the bottom. What more could you ask for?"

"This isn't a ball game, Sheldon. They aren't passing out hot dogs and beer."

"Who said anything about hot dogs and beer?"

"There aren't any Cracker Jacks."

"Well, they should provide _some_ refreshment if they expect us to sit through…" Sheldon looked at his program and gasped, "… GOOD LORD! _Three_ acts?"

"You promised to behave," Amy whispered.

Sheldon sighed. He looked as though he wanted to offer a retort of some sort, but he was interrupted by a disgruntled Howard and Bernadette who could be heard arguing near the rear of the theater. Bernadette's voice easily pierced through the gentle rumbling of the various conversations taking place around the auditorium.

"I _told_ you, I will take care of it when we get home," Bernadette growled at her husband, then softened her expression, smiling as they approached the group. "Hi guys, sorry we are late."

"Well, if _someone_ didn't insist on fixing their hair over and over again…" Howard's frustrated voice drifted off.

"Hey, you think this look just _happens_?" Raj said pathetically, peeking out from behind them. "Besides, I'm the only one in our group who doesn't have someone special in their life yet. I still need to pouf my plumage like a peacock. You know… attract the ladies." He shimmied in a very Bollywood manner, but quickly stopped after receiving a strange look from a woman standing nearby.

"Hey!" Bernadette snapped at Howard. "Raj is allowed to spend as much time as he wants to in the bathroom. At least he cares about how he looks."

"Are you suggesting that I don't care about my appearance?"

"_Do_ you?"

Howard just gaped at her, looked down at his tight black jeans, deep red velvet dress shirt and matching dickie, then gave her a conceding head bob. "Yeah, okay."

Bernadette smirked and moved to sit on the front row beside Penny's parents and Leonard.

Penny's mom smiled at them as they sat down, but quickly returned her attention to the program in her hands. Amy realized that the woman's similarity to Penny was indeed limited to her eyes and hair. Her personality was the polar opposite of her daughter's. Where Penny was outgoing and bubbly, her mother was shy and reserved. When they had finally been formally introduced that evening, Amy had only managed to hear her name – Valerie – before the woman shuffled away to her seat.

Amy didn't have too much time to consider Valerie, though, as the lights dimmed and a hush fell over the audience.

A few moments later, the curtain rose and the spotlights fell upon an empty bedroom scene. The sound of a shower could be heard off-stage, in what appeared to be a bathroom. Suddenly, Penny burst through the stage door looking positively gorgeous in her costume… a lacey, knee-length gown.

"One of those no-neck monsters hit me with a hot, buttered biscuit … so I hafta change!" she yelled.

Penny had the southern drawl of Maggie's accent down to a 'T'. She moved with the grace of someone completely familiar with the stage.

Amy reached out for Sheldon's hand and they both became lost in the play.

* * *

"I don't think I find any of these characters appealing," Amy whispered in Sheldon's ear. "I feel bad for them, but at the same time just wish they would all stop yelling at each other. I find Penny's character particularly annoying."

"It's a role she was obviously born to play," Sheldon said with a sly smile.

Amy turned to him with narrowed eyes, and Sheldon frowned.

"I _know_... I promised." He took a deep breath before continuing, his voice now rooted in sarcasm. "Oh, Amy… you're wrong. Penny's cheerful personality and wit outshines any negative aspects of the character she is playing. It's a wonder she was cast in the role at all."

Amy removed her hand from his and crossed her arms over her chest, staring at the stage.

"How can you be mad at me now?" He whispered. "I was _almost_ agreeing with you."

"Quit being such a smart ass."

"I can't stop being smart, Amy. Also, ones brain isn't in one's ass. Your insult makes no sense."

He eyed her a moment, then sighed and reached his hand out for her to take. A few years ago, she would have snatched it up in a heartbeat - but now it was different. She expected more from him. _I deserve more_, she thought. _I deserve a real apology for what he's put me through tonight._ She didn't take his offered hand. She kept her focus on the stage, and her arms crossed snuggly in front of her.

Sheldon had indeed grown over the years... especially recently. She loved him. He loved her. There had been so much change in such a short amount of time, that Amy felt guilty wanting more. But the one area where Sheldon had yet to improve was his attitude. Amy didn't want him to alter it too much - his bizarre behavior was part of what made her fall in love with him in the first place, after all. However, she did want him to at least acknowledge her feelings.

No, she wouldn't be giving in to his charming wiles so easily this time. She stared straight ahead, avoiding eye contact with him.

Sheldon eventually pulled his hand back to his lap, but Amy could feel his gaze remain steadfastly fixed on her.

* * *

At intermission, the crowds began exiting the theater to make their various bathroom runs, take a quick smoke break, or simply to stretch their legs before the conclusion of the play.

Amy peered up at her boyfriend and was surprised to see him still staring back at her… studying her. Usually she could drift away in his blue eyes, but now they were making her rather uncomfortable.

"Would you like to go outside for some fresh air?" She asked the question mostly just to focus his attention elsewhere.

"As a matter of fact, I would," he replied.

Amy nodded. "Okay, let me see if Ben and Claire – "

She couldn't complete her sentence before Sheldon was pulling her along the aisle toward the back of the theater. _Again with the pulling! _By the end of the evening, her arm was going to be removed from its socket, for sure.

"Sheldon!" Amy gasped. "I was going to see if they wanted to come with us!"

Sheldon didn't respond. He continued dragging his girlfriend along behind him, through the small lobby and back into the cool October night.

The dampened grass and moist air were the only hints that a light rain had fallen. Amy glanced to the sky and noticed that the clouds had moved away. The sky was now clear and littered with stars.

Several small clusters of smokers had congregated outside, chatting about various aspects of the play – which parts they liked, didn't like, or about the overall set design. Most were obviously avid theatergoers, self-proclaimed experts, or critics for local newspapers.

"Sheldon!" Amy finally said again, once he had pulled her all the way down the marble stairs. He waved a cloud of cigarette smoke out of the air in front of them and moved to the side of the building away from the crowds.

"Sheldon!" Amy said once more, a bit more forcefully. "What if Ben and Claire wanted to join us for some fresh air?"

"The air's not very 'fresh' out here," he argued, glaring at a nearby smoker, who heard Sheldon's comment and moved away with a scowl and a mumble. Amy wasn't nearly as bothered by the smoke, having spent so much time with nicotine-addicted monkeys at work.

"Sheldon, you've been rude to Claire and Ben all night. We should have asked – "

"I didn't want them to come."

_That's it._ She'd had enough of her boyfriend's behavior. "Sheldon, I told you earlier – "

"You said earlier that if I wanted to be alone with you, then you wouldn't be mad at me."

Amy's voice caught in her throat, and she narrowed her eyes at him again.

"My purpose was not to get away _from_ them," Sheldon continued. "It was to get away _with_ you. If you'd like to go back and get them, then be my guest."

Amy blinked. She couldn't tell if he was serious. But, despite what he may believe, he really wasn't much of a jokester. He seemed to be genuine.

"No… if that's true… then I don't mind."

"Good." Sheldon nodded and leaned against one of the large marble pillars; In fact, Amy realized that it was the same pillar they had been crushed into before the play started. She drew her arms around herself as she began to notice the chill in the air.

Sheldon groaned at her like an irritated father. "Why didn't you bring a jacket?"

"Because it's southern California," Amy snapped. "And I thought we would be indoors most of the evening."

"I suppose you want _my_ jacket?"

"No. That's okay."

"No, no… I'm given to understand it is protocol for a boyfriend to give his girlfriend his jacket in scenarios like this." Sheldon began pulling his arms out of the sleeves of his dress coat. "Though, I don't see why poor planning on the woman's part is any reason for the man to be uncomfortable."

"It's really not necessary, Sheldon," Amy insisted, holding a hand up. "It's not that cold."

Sheldon said nothing more about the matter. He flipped his jacket off of his shoulders and wrapped it tightly around her, rubbing her arms quickly to warm her up with the friction.

"Thanks," Amy gave in, bundling up in the coat. It smelled of talc, just like Sheldon. She buried her nose into he collar to breathe it in.

Sheldon nodded. He went to lean against the pillar again, but stopped himself. He regarded the marble column warily. Without barrier of his jacket to protect him from whatever was crawling on it, he opted instead to simply stand beside it.

After a few quiet moments, Amy looked up at him. He had his arms crossed over his chest, and was studying his shoes.

"Sheldon…"

He looked up at her.

"Why did you want to be alone with me?"

He shrugged and shifted his eyes to the stars. "I just did."

Amy nodded and leaned against the pillar, glancing back at the theater doors to make sure that they were not being called in from intermission just yet. The small groups of smokers were still standing together outside.

"I'm sorry," Sheldon said suddenly, drawing his girlfriend's attention back to him.

"For what?" Amy asked.

"For tonight. I'm sorry for the way I... behaved." He brought his eyes down to meet hers. "I know you were looking forward to the evening, and I … I didn't make it easy."

He was sincere. Amy could tell, because the words didn't come easily from his mouth. Each one was a struggle… as if it pained him to admit that he was at fault.

Amy smiled at him. She knew that any truthful apology on her boyfriend's part was a big deal. _He understands that he hurt me_, she thought. That was all she'd wanted.

"It's okay, Sheldon," she said. "There will be other dates."

"_Other dates_?" He groaned. "Do _I _have to be there?"

"Well, typically dates involve _both_ romantically paired individuals…"

Sheldon sucked in a heavy, annoyed breath, but nodded, as if he was accepting some kind of punishment.

"We won't do another group date for awhile, though. I promise. Just you and me." She honestly didn't feel like having another double date for a long time anyway. This one had been exhausting enough.

The lights outside the theater began flashing, and Amy pushed herself away from the pillar. The other groups began stomping out their cigarettes and moving toward the doors.

"Come on," Amy said. "Intermission's almost over."

"Wait…" Sheldon grabbed Amy's arm, which was still bundled in his coat. She turned to look at him, but the expression on his face led Amy to believe that he hadn't quite thought through what he was going to say next.

"Yes?" she asked curiously.

"I don't want us to be…" he trailed off, and looked toward the large open doors that lead back into the auditorium.

"You don't want us to be… what?"

"Like the couple in the play." He finally said.

Amy frowned. "What are you talking about?"

She thought back to the play. The main characters, Maggie and Brick, were in a sexless relationship. _Surely not_, Amy thought. _Does this mean what I think it means?_

"Sheldon… do you mean… is this about… is this about sex?"

Sheldon nearly fell over.

"Amy! Keep your voice down." He looked around, clearly embarrassed at the turn the conversation had taken. "And NO. Why must everything be about intercourse?"

_Of course it's not about sex. Get it together, Amy._

"They've been fighting the whole time," Sheldon explained. "They shouldn't be together. In fact, I don't know what even brought them together to begin with. I mean, if you consider all the people in the world, why _these_ two characters decided to join together romantically makes no sense. Let's say you figure that there were about two million people living in Mississippi in the 1950s – give or take a few thousand because of the agricultural boom in the area at that time – The odds of…"

Amy could tell that her boyfriend's train of thought was slowly derailing once again. "Sheldon…"

He looked at her.

"Your point?"

"Oh… sorry." He cleared his throat with a cough. "My point is that I don't want to argue with you. I don't want anyone to question why we are together."

"I don't think anyone thinks we shouldn't be together," Amy said. "Couples fight. It's all a part of the deal."

Sheldon stared at her with disbelieving eyes.

"Why? Who thinks we shouldn't be together?" Amy asked with a hint of anger. "Who? I'll kill them." Sure, her friends may think that she and Sheldon are strange or that they aren't a 'typical' couple, but - to her knowledge - nobody had ever questioned their compatibility. It was the one thing they were _all_ sure of. Anyone with eyes could see it… even her mother, for Pete's sake.

She started to fume.

"Amy!" Sheldon was clearly startled by his girlfriend's sudden outrage. She ignored him and turned on her heels, ready to march into the theater and 'make a scene', like Penny had taught her to do. A theater was a fitting setting for a dramatic display, after all.

"Amy! Stop!" Sheldon grabbed her arms and pulled her to him, hugging her. "I'm not talking about them. I'm talking about you!"

_Wait… what?_

Amy pushed gently away from him. Not so far as to pull herself out of his arms, but just enough to get a good look at his face.

He was being serious. The most serious she had ever seen him before in his life, at least as far as their relationship was concerned. He was legitimately worried… and she wasn't sure how to respond to it.

_Does he really think that I would question our relationship because of one night? One stupid argument?_

"But... I love you," was all she could think to say. For some reason, the words sounded bizarre... out of place. Like they weren't a fitting enough response.

But Sheldon seemed to accept it gladly.

"I love you, too," he said with relief. His hands snaked under his jacket, which still hung on her shoulders. They slid easily around her waist.

"I'm… still _trying_," He mumbled into her hair. "And failing."

Amy smiled, recalling Sheldon's confession that he'd been struggling for years not to succumb to his urges and amorous feelings for her. But slowly, day-by-day, she had been breaking down his barriers without even trying. She was unknowingly taking the metaphorical chisel to his emotional walls.

She'd blame his current behavior on her beckoning hips, but they were hidden by his jacket at the moment.

"You shouldn't try so hard. I like it when you fail at this," she whispered into his chest. "Failure isn't always a bad thing."

His arms tightened around her, drawing her into a deeper hug, and he took a large breath.

Slowly, he loosened his arms, letting them slide across her lower back, and brought his hands to a stop on her waist. She felt his thumbs rub lightly against her hipbone. His eyes were focused on his hands, studying the way the fabric of her dress moved between her skin and his finger.

_Maybe it's my beckoning hips after all?_

Amy wasn't sure if it was the chill in the air or if it was Sheldon's touch, but a shiver went up her spine.

Finally, he brought his eyes up to meet hers and without saying a word, he leaned in for a kiss.

Their lips barely touched when the lights started flashing again, indicating that the final act of the play was only a few minutes from its start. Sheldon's attention was pulled away from the moment, and he released her from his grasp.

_Drat!_

"I... um... I'll need my jacket back," Sheldon said abruptly, clearing his throat. "I'm chilly. Plus, you just look silly in it. It's not your size."

"I'll make sure I remember to bring my own next time," Amy said with a smile, removing the coat.

"That would be wise," he nodded. "Live and learn, as they say."

She grabbed his hand after he finished putting his jacket back on, and they returned to the theater lobby.

"You know, I half-expected you to drag me to the convenience store down the street so we could get some Cracker Jacks during intermission," Amy laughed.

Sheldon looked as though she'd just proposed a surprisingly simple method to see the universe beyond the limitations of cosmic microwave background radiation.

"Why didn't I think of that? That would have been brilliant!"

"Of course… spending time with me is nice, too, right?" Amy said hopefully.

"Oh… yes. Of course."

"Better than Cracker Jacks?"

"As good as Cracker Jacks."

Amy frowned.

"Cracker Jacks have a prize at the bottom, Amy."

"So do I if you dig around enough." She winked at him, hoping that he would pick up on her meaning.

He didn't.

They managed to make it to their seats just before the curtain rose for Act Three.

Amy leaned gently against Sheldon's shoulder, their hands clasped in his lap.

* * *

**Chapter twenty-seven coming soon!**

**Notes:** Reviews, por favor! :o) They make me happy. Constructive criticism is also quite nice. I won't yell at you if you hate it, I promise! Anyone who has provided me with critiques thus far can testify to that.

If this chapter seem a little long, its because it was meant to be a "setting of the stage" for the finale, if you will (theater-related pun intended). The next chapter will be the last! It's a little sad. :o(

P.S. I also wanted everyone know that when I began this story and decided to have Penny be cast in another Tennessee Williams play, I read the entire "Cat on a Hot Tin Roof" script and watched the original movie. Didn't much care for it at first... however, when I thought of it in respect to the story I was writing, I found it to be very relevant in more subtle ways than I anticipated. So, all in all, I am very pleased with the choice!


	27. Chapter 27: The After Party Conclusion

**NOTE: **You guys know I don't own these characters. They are property of the creators of The Big Bang Theory. However, there will be a few characters that are my own creations interwoven throughout. Enjoy!

* * *

***The Compatibility Constant*  
Chapter 27: The After Party Conclusion **

* * *

The conclusion of the _Cat on a Hot Tin Roof_ production was met with thunderous applause.

As the cast stood on stage to take their final bow, Penny beamed at her parents and Leonard. Her eyes met Amy's and she gave her friend a wink.

After the curtain closed, the audience made its way out of the theater. Most of the patrons immediately went outside, but a few lingered in the lobby - their own group included. They stood beside the large wooden doors leading back into the auditorium, patiently waiting for Penny to join them from her post in the backstage area.

"What did you think?" Leonard asked Penny's parents.

"Well, Leonard, we're a bit biased," Penny's father, Wyatt, laughed. "Isn't that, right, dear?" He looked down at Valerie, who simply smiled and nodded her head.

"There wasn't a single cat in the play," Sheldon sighed. "That was rather disappointing."

Leonard, Bernadette and Howard rolled their eyes.

"Well, I thought it was splendid," Hannah interjected. "I don't typically attend plays, but I may take up the hobby."

Raj tapped the redhead's shoulder to get her attention. "You know… there's an annual production of the _Phantom of the Opera_ that is held here every year that's absolutely to _die_ for."

"Really?" Hannah and Raj moved away from the group so that he could fill her in on the details, just as Penny stepped through a side door in the lobby and made her way over to them. She had changed out of her costume and into a beautiful grey cocktail dress. She immediately gave Leonard a kiss and brought her mom and dad in for a hug, before turning to the rest of her friends.

"You should be on Broadway, Penny!" Amy exclaimed. "Not in this dump of a theater."

A white-bearded man standing a few feet behind Penny looked offended. He gave a hearty "_Hmph_!" before disappearing through the same door that Penny had come through. _Probably a theater employee_, Amy guessed. Penny didn't seem to be bothered by Amy's comment, however. Quite the opposite, actually.

"Aww, thanks, Ames." Her best friend started to tear up.

"You really were quite good, Penny," Sheldon said. "And here I thought you didn't have any marketable skills."

Penny frowned, but hugged Sheldon anyway. "Thanks, sweetie. That means a lot coming from you."

"Let go of me, please," Sheldon said matter-of-factly. Penny released him and backed away, smiling at everyone.

"Listen – The after party for the cast and crew is right down the road. Family and friends are invited. I want you all to come!"

Amy looked at Sheldon. She wanted to spend some more alone time with him. They'd been interrupted during intermission, and she really wanted to pick up where they'd left off.

"I don't know, Penny," she said. "I know I said that we would, but I think we might just head home instead. It's getting rather late."

"No!" Penny grabbed Amy's arm. "Amy, you _have_ to be there. You promised." There was a panic in Penny's eyes that Amy couldn't pinpoint.

_I guess she just can't bear to be away from me, A_my thought.

"You want to come, Sheldon… don't you?" Penny pleaded. Her friend's eyes met her boyfriend's and they stared at each other a moment.

_Oh, Penny, you know better than that,_ Amy thought.

"I agree with Penny," Sheldon said, keeping his eyes on the actress. "I think we should attend."

"_You do_?" Now Amy was really confused. Sheldon just kept surprising her tonight. "Why?"

"Well, we were invited," he said. "And, as I've come to learn, it is rude not to accept an invite of a friend. You taught me that, in fact."

"Did I?" She racked her brain trying to remember. It definitely sounded like something she would say. Although, now she was regretting being such a busybody.

Sheldon nodded. "Yes. Remember? Even if I don't want to go, I have to pretend that I do. I'm told that it's polite."

Penny frowned at him.

"Not that I don't want to go," Sheldon added, quickly. "It sounds like a hoot and a half."

Amy looked at him in shock. Satisfied, Penny smiled and turned her attention back to her parents and Leonard.

Sheldon leaned in to Amy. "Bazinga," he said with a smile.

Amy grinned. _There he is._

Since they rode together, Claire and Ben were beholden to whatever Sheldon and Amy were doing; But Claire didn't seem to mind. In fact, she was excited at the prospect of spending some more time with everyone, and Ben begrudgingly followed after her.

"Well, if we are going to go to this thing, we'd better head that way," Amy said. "Let me find Hannah so I can tell her goodbye."

Amy searched the crowd for her coworker, finally finding her outside with Raj's arm looped in hers. The astrophysicist was pointing out constellations in the clear night sky.

Amy gaped at them_. When the heck did this happen?_

"Your hair reminds me of the amazing ultra-red galaxies," Raj said. "Have you heard of them?"

Hannah shook her head.

"The Spitzer telescope discovered them a few years ago. They are the brightest red galaxies ever found. They're beautiful."

"Really?" Hannah looked toward the sky. "Where are they?"

"You can't see them with the naked eye," Raj shrugged. "They're too far away. Probably some of the most distant galaxies we've ever captured photographs of."

Hannah looked disappointed. "I'd love to see them."

"I could… take you to the university sometime?" Raj said, hopefully. "If you want to see them I mean."

"Really?"

Raj nodded. "I have a really big telescope."

Hannah giggled at his unintended double-entendre, causing him to blush.

"That's not what I… I mean to say… my telescope… It's – "

"I'd love to see your telescope."

"You would?" Raj looked surprised.

"The one at your lab," Hannah clarified.

"Oh, yes. Of course."

"You coming?" Amy called to Raj, pretending as though she hadn't been eavesdropping.

Raj and Hannah turned to her, startled. They immediately let go of each other and took a step away.

"Would you mind if I invited Hannah to the party?" he asked Amy, as if Hannah was her teenage daughter.

Whether intentionally or not, Hannah seemed to fall into the parent-child paradigm as well. She stood behind Raj giving Amy a thumbs up with a big, impish grin - silently begging Amy to let her spend more time with him.

"Not at all," Amy smiled, taking the hint. "I'd love for her to come along. And I'm sure Penny wouldn't mind."

Hannah beamed at her, but she wiped the smile from her face when Raj twisted around to look back at her. "What do you say? Do you want to come?"

"Sure, I guess," Hannah shrugged, nonchalantly.

_No need to play it cool, Hannah, _Amy laughed to herself._ Raj is already twitterpated._

When Raj and Hannah joined the group, everyone slowly made their way to a hotel two blocks down from the theater where Penny's director had reserved the conference room for their gathering.

Sheldon reached out to grasp Amy's hand as the group strolled down the sidewalk.

* * *

As irony would have it, the theater director was a man by the name of Bob Roberts, who was indeed the same gentleman whom Amy had unintentionally insulted in the theater lobby. He pursed his lips at Amy as he shook her hand.

"Thanks for inviting us," she said with a smile. It was too late, however. The man's impression of her was clearly not going to change any time soon. He merely grunted an acknowledgement of her appreciation, and directed his attention to the next person in line – Howard.

"Your name is Bob Roberts?" Howard asked with a childish grin, as he was introduced.

The bearded man nodded his head.

"So… 'Robert' Roberts, then?"

The man nodded again. He was obviously accustomed to being teased, and refused to give in to the tiny man's jokes.

"Ok. Just checking," The engineer held up his hands and scooted away.

The conference room for the after party was packed tighter than sardines. _This has to be torture for Sheldon_, Amy thought. She glanced up at him, and – as she predicted – her boyfriend had his arms crossed in an attempt to make his body as small as possible, so as to prevent bumping into others.

"You okay?"

He shook his head. "Of course I'm not okay. Do you realize how many code violations this place probably has right now? We'd be killed if there were a fire, for sure. And I heard a child cough earlier. We've probably all been infected with something."

Amy rolled her eyes, but she'd expected as much.

"I'm going to find the spot in the room that is the least densely populated." Sheldon squeezed his way through the crowd, stopping every so often to karate-chop in the direction of someone who bumped into him.

"He really is an odd one, isn't he?" Amy turned to find her dad, seated in his wheelchair next to her.

She nodded at him, and smiled at her mom, who was James' personal chauffeur for the evening.

"Well, Amy, dear," Carol began. "I should probably let you know that your father and I have finally found a new home."

"Really?! That's great!"

"Yes, and not a moment too soon," James added, pointing at his cast. "This leg is torture for me going up and down the stairs."

"Plus I won't have to put up with you and Sheldon talking business and… other nonsense… all the time," Carol said.

James laughed. "Oh, honey, I have a feeling Sheldon's going to be around for awhile. There's plenty of nonsense to come, I'm sure."

"Well… that may be," Carol conceded. "But it won't be an every night occurrence. I can only stand so much of it. I don't understand a thing you boys talk about."

"When do you move into your new house?"

"Not for a couple of months yet, what with closing and all," her mom explained. "But we are not going to renew our rental this month for the apartment. We're going to pack everything up and go live with your Aunt Edith in Glendale until all the paperwork is finalized. It'll save us some money… and your dad will be able to get around easier."

"Actually, we could use your help packing some things up tomorrow, Button," her dad said. "If you don't mind?"

"Of course I don't mind! I'd love to help!" It took everything Amy had not to show just how exciting this news actually was for her. She loved her parents so much, but yearned for the days when she could visit Sheldon without worrying about bumping into them in the halls and falling victim to a guilt-trip from her mother about not visiting enough.

The harsh squeal of a microphone caused everyone in the room to grimace and scowl in the direction of the offending sound.

"Sorry," Bob Roberts was untwisting his microphone cord, in preparation for his speech. He stood on a small platform that had been brought in for the occasion. The crowd continued to chatter as he said a few brief words of thanks to the cast and crew before handing the mic over to his lead actress, Penny.

The blonde tapped her spoon on her champagne glass to get everyone's attention.

"Excuse me, everybody, I have something important to say!"

Slowly, the room quieted down and everyone turned to Penny.

"I want to thank everyone for coming to the play - especially those who came from so far away. Mom… Dad… I'm glad you both could make it. I hope it was worth it."

Everyone clapped. Wyatt and Valerie beamed with pride at their daughter.

"I want to give a special thank you to my friends and family who have always supported me, and helped get me this far."

Their group looked at each other and smiled. Amy stuck two fingers into her mouth and whistled loudly at her friend, which garnered bizarre looks from everyone in the room… even Penny.

"_Anyway_… now to the real reason I'm up here," the actress continued. "I don't know if many of you know my boyfriend, Leonard." She pointed him out in the crowd and he waved to everyone. "Leonard, come up here."

The smile fell from Leonard's face and he nervously approached the stage.

"Leonard's always been there for me. And I haven't always been the easiest person to deal with." She paused to smile at him. "But, there was something I wanted to do tonight. And I really hope it's okay…"

Penny pushed the microphone into its stand and turned to Leonard. She grabbed his hands and stared into his eyes for a moment before squeaking out a '_Hoooo boy_!', taking a deep breath, and slowly dropping down onto one knee in front of him.

"_What the_…?" Leonard took a step back.

Penny held a tiny, silver paper bag up to him.

"What's this?" He asked. Leonard took the bag from his girlfriend and peeked inside.

"Leonard… I have never been as happy as I am right now - with you. I know I've been dragging my feet, but… I'm ready now," She took another deep breath. "I know we agreed that when the time was right, I would ask you to marry me. But, I decided that I don't want to do that."

"What?" Leonard looked around at the crowd. Every eye was on them. He leaned in and whispered softly enough so that only the people closest to the stage could hear. "_What do you mean_?"

"I decided I don't want to ask you to marry me," Penny repeated. She straightened her back, but remained on one knee. "Leonard Hofstadter - will you please do me the honor of asking _me_ to marry _you_? … One more time."

Everyone gasped and Leonard's jaw hit the floor. "Seriously?!"

Penny smiled at him, still on her knee. "Look in the bag, sweetie."

Leonard reached in and pulled out a little black velvet box. He popped it open and a simple ring with a single diamond shone from inside.

He stared at it a few moments and the crowd began whispering.

"Well?" Penny asked. "Knee's starting to hurt here, honey. What do you say? Will you ask me?"

Leonard immediately dropped down to the floor next to his girlfriend, tears starting to form in his eyes.

"Yes! Yes, of course!"

"Well?" she nudged him playfully. "Go ahead." Amy could tell that Penny was trying to play it cool and stay strong for Leonard, but the way she was biting her lip gave her away. Penny's eyes were slowly turning red, holding back the tears.

Leonard looked down at the ring in his hand and turned it over in his palm a couple of times before finally holding it out to Penny, who feigned surprise with another playful, nervous giggle... a tear finally finding its way down her cheek.

"Penny… will you… will you marry me?"

She paused a moment and another hush fell over the crowd.

Then, she grinned at him.

"Yes."

The two lunged towards one another, littering each other with kisses as the crowd clapped and cheered.

Amy couldn't believe it. _How could Penny have kept this secret from me?_ She felt like she should probably be offended, but she wasn't. She was just happy for her friends. They deserved this. Besides, she'd been so absorbed in her own Sheldon-centric world that she hadn't bothered to check in to see how Penny and Leonard's relationship was progressing. _It's my own fault, really,_ Amy thought to herself. _I'm slacking on my BFF duties._

She considered running to congratulate the couple, but they were already swarmed with people.

_There should be an express lane for best friends_, Amy thought with a frown, but decided to meet up with her bestie later.

She instead looked through the masses of people for her own boyfriend. Finally, she spotted him across the floor, trying to stay as far away from the mob as possible. To Amy's surprise, he was standing beside Ben, who was evidently trying to keep away from the crowd as well.

Amy locked eyes with Sheldon and they smiled at each other. He motioned his head toward the large front door of the room. Amy nodded, and began walking that way to meet up with him.

_I can't believe my best friend is getting married_, she thought. _It's about time! Now maybe I can use that tiara again!_

She looked back at Penny and Leonard. Penny had the ring on her finger, and was showing it off to her parents. Leonard was grinning ear to ear, and couldn't take his eyes off his gorgeous fiancé.

Amy and Sheldon reached the door at the same time.

"Did you know about this?" she asked, pointing in the direction of the newly engaged couple.

Sheldon nodded. "Yes. Penny told me earlier today."

"Why didn't she tell me? I'm her best friend."

Sheldon shrugged. "I don't know. She said she didn't want anybody to know. I'm not entirely sure why she told _me_, to be honest. She knows I can't keep a secret. I had to leave the apartment all day just so I wouldn't be around Leonard and accidentally spill the beans."

Amy looked back at Penny, who glanced her way and winked at her.

So, that's what she was up to. _Oh, she's good_, Amy thought.

"Well, I – for one – am glad that she told you," Amy said, returning her attention to Sheldon, who looked positively confused.

"You and I wouldn't have spent the day together," she explained.

"Oh. Yes," Sheldon nodded. "That was... surprisingly nice."

"Surprisingly?"

"Well… considering the exchange of saliva that has been taking place lately."

Amy smiled. "Would you mind if I kissed you now?"

"In front of all these people?" he asked.

"Their attention is diverted," Amy pointed out. "They are all fawning over Penny and Leonard."

Sheldon glanced toward the crowd, and then looked back down at her with a frown.

"Looks like you are right," he said, disappointed.

"Don't you… _want_ to kiss me?" Amy said hopefully.

"Not really, no." Sheldon admitted. "I don't mind... I mean.. I _enjoy_ kissing you, Amy. More than I thought I would. But there's no need to make a display of it. We aren't art installations for people to gawk at in a museum."

"Oh," Amy pushed herself back on her heels, feeling rejected.

Sheldon frowned at her.

"Hang on," he groaned. He looked around the room, then popped the door open and stuck his head out into the hallway.

After a few moments, he brought his head back in and grabbed Amy's hand.

"Come with me," he said.

Sheldon pulled Amy out the door and down the hallway to the restrooms. There was a unisex room, intended for families with small children.

Sheldon glanced back and forth down the hallway once more, then pushed the door open and dragged Amy inside.

"Oh!" Amy exclaimed as he shut the door behind them and locked it.

He turned to her and they stared at each other a moment. Then, Sheldon took a couple of quick steps forward.

"Mm!" Amy moaned in surprise as his lips met hers.

He pressed his mouth against hers, and she moved her lips back, encouraging him to keep going.

She wrapped her arms around his neck, and pushed herself softly against him.

She could feel Sheldon gently placing his hands on her hips again.

_Yes… He's finally giving in,_ she thought. But his grip slowly tightened on her waist, and suddenly Amy was being pushed away from him.

_What? No!_

"Hold on, Amy," Sheldon said.

"What's wrong?" she asked, frustrated. "There's nobody in here."

She looked around. The toilet wouldn't have been her first choice for the first _real_ full-on make-out session with her boyfriend, but it was a rather nice restroom, actually. There was a loveseat and a large potted plant. The whole room smelled of lavender hand soap.

"What is it, Sheldon?" She asked again, when she received no response.

He was breathing heavily and his eyes were concentrated on the floor.

"I don't know," he said, shaking his head. "I just… I don't know."

"We were only kissing, Sheldon."

"I know."

"We've kissed before."

"I know."

"I love you."

"I know."

"Do you want to leave?"

"No."

"Do you want to sit?"

At that, Sheldon's eyes met hers and he looked at her like she was mad. "In here? The _restroom_? I'm not touching anything in here."

"It looks fairly clean," Amy said with a shrug, looking around again at the counters and the small loveseat.

"So do most grocery cart handles… and doorknobs," Sheldon said indignantly.

"Ok… well... what is it, then?"

He looked around the room again, and then held his hand out to her.

"Come here," he said.

She looked at his hand hesitantly, but finally took it and slowly walked toward him. _What is this all about?_

"Amy…"

"Yes?"

"I want to discuss something with you, and I want you to keep an open mind."

"O… K…."

"I would like to change the Relationship Agreement."

"O… K…"

"By that, I mean… I want to get rid of the Relationship Agreement."

"What?! Why?" _Get rid of the Relationship Agreement? Is he crazy?!_

"Because the document is no longer is beneficial to either party."

"What do you mean? Of course it is. I – "

"Clearly, the parameters of our physical relationship have changed since we last altered it. And the clauses related to family gatherings have all but been ignored."

"But…"

"I'm just saying that every time we do something that is in direct violation of the agreement, I can't stop thinking about it. It eats at my thoughts like some kind of parasite. Just now, for example… what we are doing is in direct violation."

"But…"

"And every time we have seen your family, I can't help but dwell on the fact that it is going beyond the limitations set forth in our signed agreement."

"But..."

"I'm not saying that I don't want to see your family. I enjoy spending time with them. Your dad, especially. He's made me feel like I _belong_ in your family. I've bonded with him more than I ever did with my own father. But, regardless of my feelings, it is prohibited in the agreement. Honestly, I don't know why I've let it go on this long."

"But…"

"Now, we could sit down and have another session where we rewrite the whole thing. Start from scratch. But, I just don't see the point."

_How could he be saying this?_

"You don't see the point? But, Sheldon… it's our _agreement_. It's what is holding us together. It's proof that we are a couple."

Sheldon shook his head. "No, it's not. We've never followed it. Not really. I'm not an idiot."

"So, you'd rather just _not_ have an agreement? You'd rather just pretend we are a 'normal' couple? We aren't normal, Sheldon," Amy argued. "And I like not being normal."

Sheldon smiled. "I like that, too."

"Well?"

"We'll never be normal, Amy. Relationship Agreement, or no."

Amy couldn't believe what she was hearing. In the past, she would have loved to take a lighter to the document that put so many restrictions on their relationship, but now that Sheldon was actually suggesting it… the thought scared her.

"So… you want to just completely disregard our agreement?"

"Not disregard. _Nullify_," Sheldon corrected. "I can't just completely ignore something that we have signed and that is still in effect. Otherwise, I will be stuck thinking about it just floating around out there. Like right now. I am thinking about it _right now_. We were making out, and I couldn't stop thinking about it being a violation of our current agreement… something we _both_ signed and promised to uphold. It's distracting."

Amy smiled at Sheldon's use of the phrase 'making out'. She never thought she'd see the day.

"Well, let's get rid of it then," Amy said. She started walking toward the door.

"Where are you going?" Sheldon asked.

"Well, Sheldon, completely nullifying the agreement will require both our signatures on the document," Amy explained. "Plus you don't have your notary stamp with you. We will have to continue our … interaction… later."

Sheldon frowned. "You're right."

Amy shrugged. "Later, then." She clicked the lock on the door to the 'unlock' position.

"Wait," Sheldon said. "I have my iPad in your car."

"So?"

"I have the document on my iPad. I keep all important documents in a locked folder on it."

"Ok?"

"We can both sign it, and we can agree that the document is no longer valid. That should suffice until I can get to my notary stamp."

Amy considered him for a moment. "Are you sure you want to do this?"

"Yes."

"Sheldon… really think about this. Think about what you are saying."

"I already have."

"So, you're comfortable with us having no limitations on what we do together?"

He shifted on his feet. "Well… I wouldn't say I'm _comfortable_ with it. And I certainly wouldn't be jumping into anything too serious. I just don't want this agreement dangling over my head… taunting me… every time we break the rules. Which you seem very keen on doing lately. Something has to give."

The couple stared at each other for several seconds, before Amy finally popped open the door to the bathroom. She stepped back into the hallway – taking a moment to make sure that nobody would see them emerge from the bathroom together – and then turned back around to look at Sheldon.

He hadn't moved. He was still taking in her reaction to his proposal.

She finally held open the door for him, and motioned her hand down the hallway.

"Lead the way."

* * *

The car was dark.

Amy hadn't bothered to put the key in the ignition. Once they had both settled into the back seat, neither had made a move to turn on the overhead light.

It was silent too, except for the cars driving on the nearby road and the heavy breathing of the two individuals in the car … and, of course, Amy's thoughts.

_This isn't really happening. It can't be. _She still expected at any moment that Sheldon would mutter "Bazinga!" and start laughing.

As her eyes adjusted to the darkness, Amy was surprised to see that Sheldon was staring at the iPad in his lap. She hadn't heard him pull it out of his bag.

"Sheldon… ?"

Suddenly, the car was illuminated by the light of the gadget as Sheldon clicked it on.

He slid his finger across the screen and began tapping away, searching to for the document in question. Amy knew that he'd found it when his finger stopped moving and he looked up at her.

"Here it is."

Amy looked at him again, not sure if he was really wanting to do this.

"Sheldon…"

"Don't, Amy."

"Don't what?"

"Don't try to talk me out of this. I've made up my mind. I made it up last week."

"I don't want to talk you out of it. I just want to make sure you know what you're doing."

His eyes met hers. By the artificial light of the iPad, bizarre shadows formed on his face that made him look like he was wearing a mask over his eyes.

_My superhero._

"Of course I know what I'm doing, Amy. I'm a genius."

"You're also a theoretical physicist. Which means, by definition, you are trying to _figure out_ what you are doing… i.e., you have no idea."

Sheldon narrowed his eyes at her.

"Just want to make sure you've thought it through. I don't want you to hate me for this later."

"I never do anything without thinking it through," he said firmly. "And… I will never hate you. Just… take this and sign."

Amy took the gadget from his hands and tore her eyes away from his to study the document on the screen.

...

**_**Relationship Agreement: Termination**_**

_A termination of the Relationship Agreement requires signatures of both The Girlfriend and The Boyfriend._

_Once signed by both parties, all requirements, benefits, and standards set forth in the aforementioned agreement will be null and void, effective immediately._

_..._

That was it. So simple. All she had to do was sign, and she would have freedom to do whatever she wanted with her boyfriend. No more silly requirements or advanced notice for gatherings or outings, no more restrictions on physical contact, no more prescheduled date nights.

_Then why does this feel so … wrong?_

"Before I sign… I need to know something," Amy said.

Sheldon nodded. "Ok. What do you want to know?"

"This agreement has always been _mutually_ beneficial," Amy said. "Just… tell me that you aren't trying to get out of your obligations to me. If this is really just a ploy to lay the foundation for a future break up... just ... tell me now."

Sheldon gasped at her accusation. "Amy! First of all... if anything, the Agreement's benefits already skew slightly in _my_ favor. Secondly, all of my ploys that you didn't help me with have always ended in horrible failure."

"Then… I guess I just need a better explanation. You say that you don't want to be burdened by our agreement, but you aren't burdened by your Roommate Agreement... so why do you feel 'burdened' by ours?"

"The Roommate Agreement is different."

"Why?"

"Let me put it this way, Amy. Leonard is my best friend. The Roommate Agreement is the contract for our cohabitation, not for our friendship. If Leonard ever needed anything from me as a _friend_ – I wouldn't hesitate. The restrictions outlined in our Roommate Agreement would not have any bearing on that relationship. You and I… our relationship is important to me. And I've come to realize that ours is not the type of relationship that can be limited by a contract."

"People sign marriage contracts all the time."

"We aren't getting married."

"Really? Never?"

"Well… I never thought that I would get married. But, like coitus, I'm not going to rule it out either. Certainly, neither will be happening soon. So, let's not get ahead of ourselves."

Amy frowned. "But…"

"Just… just listen to me for once." His frustration was becoming evident. "I've found myself approaching our relationship the same way that I do my work. I'm passionate about my work, Amy. I think about physics almost constantly… it encompasses my life. And I like it." Sheldon took a deep breath before continuing. "The only thing that I think about as much as physics is ... _you_."

"I don't put limitations on my advancement at work," he continued. "I couldn't even if I wanted to. Then it hit me – just like the solution to the movement of electrons through graphene. I realized… I shouldn't limit myself in our relationship, either. Nobody puts limits on Sheldon Cooper's interests. Not even Sheldon Cooper."

The car was silent for several moments while the two stared at each other. Eventually Sheldon began squirming awkwardly in his seat.

"… That was it. That was my speech," he said. "Now sign it."

Amy didn't hesitate. She used her finger to quickly sign her name on the line and then passed the device back to Sheldon.

His finger hovered over the screen for a moment, studying her signature. He then took a breath and swiftly glided his forefinger over the line meant for him.

_That's it. It's done._

It felt so final.

Sheldon let the light dim on the iPad, before it finally shut off on its own.

Neither said a word.

Amy had studied the phenomenon of "phantom limbs" in the past. She'd been fascinated by the notion of the brain perceiving signals from amputated arms or legs. But, these occurrences could be explained by a number of neurological studies, some involving the reorganization of the primary sensory cortex of the brain. She understood this. It was science. It was tangible.

She imagined _this_ is what the phenomenon would feel like. The Relationship Agreement no longer existed. It felt like something important was missing, but still there at the same time. Yet, their contract had never been a part of her physical body - so how could it feel the same as a missing arm?

_How bizarre._

"So…" Amy began, waiting for direction from Sheldon.

He said nothing.

Without the glow of the iPad it was difficult to see his expression, but she could still make out his silhouette.

She decided that the only way to get over the feeling of loss was to test the waters of their new relationship paradigm.

"So…" She repeated, shifting closer to him in the seat.

Still he said nothing, but a sound of confused nervousness squeaked out of his throat as she drew closer.

Amy held a shaking hand up between herself and her boyfriend.

"Since there are no longer any limitations… I could…" She pressed her hand flat against his chest. "Do this?"

His breathing increased in speed, and she felt his heart racing against her palm, but she could see him nod.

"And I could…" He raised his hand, ready to mimic her motion by placing it on her chest, but at the last second changed his mind, bringing his hand to rest on her thigh. "Do this?"

It was Amy's turn to nod.

"And then I could…" She thought a moment. It was important to choose something that wouldn't scare him away. She glanced up and down at him, though mostly she was using her memory of what Sheldon looked like. It was too dark to actually see anything. Of course, she had long ago burned into her memory every curve of his face… every angle of his lanky arms and legs. Oh yes - Amy knew her man.

Finally, she decided to simply set her arm on his. She gently placed her hand over the one he had on her thigh.

"… Do this." She said it with finality. It was no longer a question.

Sheldon swallowed. "And I suppose I could…"

He paused a moment, weighing his options, and then inched closer to his girlfriend - his hand naturally moving up her thigh in the process.

He leaned in slowly, his face a mere foot or so from hers.

"… pick up where we left off inside?" he asked.

"You mean…?"

He closed the distance between them, placing his lips gently onto hers.

Amy brought her hand from his chest up to his neck, holding him in place as she moved her lips against his.

Without the restriction of the Relationship Agreement looming over him, Sheldon seemed a bit more at ease. He was no longer breaking his own rules. It was as though a weight had been lifted off his shoulders. He was more adaptive to Amy's movements. He didn't even wince as her lips parted against his, and his own lips followed suit. They fumbled a bit, but kept up with each other's pace.

His hand left her thigh, and found her face in the darkness. His fingers became tangled in her curled hair near her ears, and Amy's free hand moved to his shoulders, sliding underneath his coat. He flinched a bit at her touch, but quickly relaxed.

She knew he wouldn't allow her to go much further - and she wasn't ready to go much further herself - but their closeness in that moment was exhilarating.

"Here they are! I found them!"

Amy pulled away from her boyfriend to see Howard's face smushed against the window. She had never been unhappier to see that tiny, obnoxious man.

Sheldon quickly distanced himself from Amy and wiped his mouth on the back of his hand as Howard began tapping against the window.

"Hey guys! Whatcha doin' in there?" He laughed. He knew perfectly well what they had been doing.

Amy rolled her eyes, and Sheldon must have seen her, because he sighed as well.

"Perfect," he said. "What do we tell them?"

"You could just tell them the truth. You were making out with your girlfriend." She grinned.

"Be serious, Amy."

"I am being serious. We were caught in the act, Sheldon. I don't know what else you could possibly say?"

"I'm sure there's something…"

"Oh, sure. There are a lot of reasons we could be _here_… in the backseat of my car… in the dark… with our mouths together."

"Exactly. Perhaps you were… choking?"

"On your tongue?!"

"Of course not! And for the record… there were no tongues involved in this exchange. I don't want this encounter to be exaggerated when you inevitably blab to Penny and Bernadette."

"Oh… there's no need for exaggeration. I will tell them every detail exactly as it happened."

Somehow, Amy could tell that Sheldon wasn't entirely comfortable with that idea either.

"Let's go," Amy said. "We are just delaying the inevitable."

Sheldon ceded with a nod, and pushed open the door. The two of them shuffled out of the car and were immediately greeted by practically every person in their group.

Penny was gaping at them from behind Leonard, who had obviously been trying to pull her away from the very private scene.

Claire was beaming at them, but Ben was positively scowling. This meant Claire would probably be pushing him to do more, using Sheldon and Amy as an example.

To Amy's horror, her parents were also lurking nearby, trying to maintain their distance.

In fact, the only people who were not there were Raj and Hannah – and judging by their interaction earlier in the evening, Amy would be surprised if she saw either of them again for some time.

"Well, well, well…" Howard said knowingly. "What do we have here?"

Sheldon moved to hide behind Amy, but she would have none of it. She grabbed the arm of his coat and pulled him back around beside her. They were going to deal with this together.

Bernadette elbowed her husband in the ribcage. "Howie! Honestly!"

"Hey!" He held his arms up in surrender. "Let the man who has not made out with a woman in the backseat of a ragged out car cast the first stone!"

"My car is not 'ragged out'!" Amy argued.

"Howie! Enough!" Bernadette grabbed him and began to pull him away. She turned back to Amy and mouthed '_I'm sorry'_, before unlocking her car door and shoving her husband inside.

It was then that Amy realized exactly how disheveled she actually was. She glanced down at her dress and twisted it back into place. Her glasses were slightly askew, so she repositioned them on her face.

She cleared her throat before addressing the group collectively.

"So… umm… were you all wanting something?"

Ben spoke up right away. "We were wanting to leave."

Claire grimaced at her boyfriend's lack of tact.

"We were all just wondering where you two had gotten off to," Penny said, biting her lip.

"Leonard," Sheldon asked calmly. "A word?"

His roommate nodded and the two men wandered off to a more secluded part of the parking lot.

_What's that all about?_ Amy thought.

Penny walked up and gave her friend a hug.

"I wanted to thank you for coming tonight, Ames," she said. "It really meant a lot to have you there."

"Oh, yes! Let me see your ring!" Amy said enthusiastically. This had indeed been an important evening for her friend. With everything that had happened between Sheldon and herself that night, she had completely forgotten about her bestie's big news.

Penny held her hand out to Amy to show off the jeweled band.

"My parents didn't know anything about it," Penny explained. "Nobody did, except for Sheldon of course. It took a lot of convincing for my mom to make the trip without telling her why. I don't know what she thinks of Leonard yet. She hasn't really said much. Of course... that's just how she is."

She sighed, and a small frown formed. But she quickly put a smile back on her face and looked back at Amy. "Leonard's already upset because he didn't have a part in picking the ring out. We are planning to go back to the store and poke around a bit to see if there's something else he would like me to have. But, honestly, this is the one I wanted. We'll stick with it, I'm sure. I'll just let him buy me something else. Maybe some matching earrings!" She winked at her friend.

"Wow," Amy couldn't stop her eyes from tearing up with excitement for her best friend. "What a special night for you!"

"_Looks like it was a special night for both of us…"_ Penny said out of the side of her mouth with an elbow nudge.

Amy blushed. _That's the understatement of the century. _"I'll give you the details later. I've got to get Ben and Claire home."

Penny nodded. "We'll have a girls' night soon." She kissed Amy on the cheek then turned away to look for Leonard.

Carol wheeled James over to her daughter as soon as Penny was gone. Her mom cleared her throat awkwardly. "I can't say I approve of your behavior tonight, Amy," she said firmly, with a gaze that could pierce into Amy's soul.

Amy tucked a strand of her hair behind her ears, and glanced awkwardly away. She had no excuse. There was nothing she could say.

"Oh, give the girl a break," James came to Amy's rescue. "She's a grown woman."

"Thank you, daddy."

"Aw, Button," he said. "Don't go thanking me. You know I love that Sheldon boy. Just… take it slow, hm?"

"Oh… believe me, dad," Amy rolled her eyes. "We're taking it slow."

"Alright, alright," Carol jumped in. "Let's get home. My feet are killing me. We'll see you tomorrow, dear. Be sure to dress comfortably so you can help us pack."

She hugged her parents goodbye, and watched them leave. She loved having them so close, but she couldn't wait to get some of Sheldon's attention back from her father. Especially now, since she and Sheldon were becoming more… intimate. She promised herself that she would still find the time to regularly visit them at their new house. Sheldon would want to continue his friendship and business partnership with James, after all.

"Are you two ready?"

Ben and Claire both nodded, and Amy held the door of her car open for them.

Ben slid in, but Claire hesitated outside the car for a moment.

"Amy…"

"Claire?"

"I know you are _Ben's_ friend, but… I don't have many women that I am close too. I feel like we really connected today. I'd like to see you again… without the men causing trouble for us. If… if that's okay?"

Amy beamed. Another friend? She was quickly becoming the most popular person in their group. _If only the high school cliques could see me now!_

"Of course! You should come to our next girls' night! It's a blast. I think you'd fit right in!"

Claire smiled softly. "I'd like that very much! Thank you, Amy."

The blonde disappeared into the backseat next to Ben, and Amy closed the door behind her.

Amy then scanned the parking lot for Sheldon. He was still talking to Leonard, but Penny had joined them.

_What could they be talking about?_

Sheldon's eyes caught hers, and when he noticed her inquisitive stare, he quickly bid Leonard and Penny farewell and trotted over to his girlfriend.

"What was that about?"

"Oh… nothing."

"Don't '_nothing'_ me. What were you discussing with Leonard?"

Sheldon didn't answer. He instead walked past her to the passenger side of the car.

"Sheldon." The firmness in Amy's voice caused him to look her in the eye. "Trust. Remember? You can tell me anything."

"I… just…" He swallowed. "I just had to ask for some advice."

"Advice?"

"Yes. It's a guy thing. You wouldn't understand."

"Try me."

Sheldon glanced down through the window into the backseat, where Claire and Ben were waiting.

He lowered her voice to a whisper.

"I had to ask him about… women."

"Well, why couldn't you just ask me? I'm a woman."

"Honestly, Amy. Why are you making this so difficult? You have girls' night for this kind of talk. We guys don't really have that sort of thing. I don't ask for all the details of your girly chatter. I'd appreciate you extend me the same courtesy."

"Oh!" She nodded in understanding. "Sure. I mean... of course!"

Now that she grasped his meaning, the curiosity was overwhelming. But, she bit her tongue and smiled to herself. She could suffer through a little curiosity if it meant Sheldon was eager to discuss their relationship with his best friend.

Amy popped open her car door and Sheldon did the same.

She wasn't sure what was ahead for them. Without a Relationship Agreement, it all seemed so very... risky. But the good kind of risky. The kind that meant anything could happen.

* * *

**The End.**

* * *

**Notes:** I hope you have enjoyed it!

This last chapter just kept smacking me right in the feels over and over as I was writing it. I hope it did the same for you.

This is where I wanted this particular story to end, but I do have some ideas for additional stories, and I would like to get your opinions. I will honestly take your thoughts into account.

I could either do a continuation (Part 2) of this one, or I can do a completely new tale. Which would you all prefer? My ideas would work for either endeavor. There are advantages and disadvantages either way. Let me know what you think, please! You can either PM me, or you can leave me a review with your thoughts. If I end up not doing a continuation of this story, I MAY do an epilogue.

I will be taking several weeks off from writing, though, just to regroup and get a new story outline together (and to enjoy the start of Season 7!).

Thank you once again for reading, and to those of you who regularly reviewed (you know who you are) – I want to give you a very special thank you! You honestly kept me going! You have no idea how much I loved reading your reviews and critiques.

For those of you lurkers — I want to thank you, too! I appreciate your interest! I do hope you leave me a final review to sum up your thoughts on the story as a whole. :o)

**Another note:** I am realizing now that many of you may not understand the "twitterpated" reference in this chapter, as it is not an actual word. That is a reference to Disney's "Bambi". I just felt I should explain that one, lest people who have not seen the movie get confused. I hope you can infer from context what it means. haha


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